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View Full Version : Big Bang simulated in metamaterial shows time travel is impossible



Smileycat
04-15-2011, 10:30 AM
According to this article at physorg.com: http://www.physorg.com/news/2011-04-big-simulated-metamaterial-impossible.html

An excerpt:
By observing the way that light moves inside a metamaterial, researchers have reconstructed how spacetime has expanded since the Big Bang. The results provide a better understanding of why time moves in only one direction, and also suggest that time travel is impossible.

I wonder if this means it would be possible if there was no Big Bang? For those of you who studied the Bible at all, God is defined as "I am the Alpha and the Omega, the Beginning and the End,: says the Lord, "who is and who was and who is to come, the Almighty," in Revelation 1:8.

May I have your opinion?

Zoombie
04-15-2011, 10:32 AM
Well, at least this means free will still exists!

whistlelock
04-15-2011, 10:39 AM
We already know time travel is impossible.

No one has come back to tell us they're from the future.

And, frankly, I doubt people from the future are any better at keeping secrets than we are today.

Smileycat
04-15-2011, 10:41 AM
Well, at least this means free will still exists!

Hi, Zoombie. I just want to understand what you're saying. Do you think that if time travel were possible and the Big Bang is THE theory of how we started, free will would be questionable?

I think some things are preordained, so to speak. But I do think we have choices to make which can deeply affect our lives, too.

Thanks for your opinion.

kuwisdelu
04-15-2011, 10:43 AM
Eh, this doesn't really convince me of anything. It's already pretty much accepted that general relativity is incomplete, and there are new theories that even gravity is only an emergent phenomenon rather than an actual force. Which — on a sidenote — makes me think it would be interesting if time is similar in that regard. But I don't see any rigorous justification for concluding anything at all from this.

Besides which, it depends what is meant by "time travel." Are we talking about going back in time? Because traveling forward in time has already pretty much been demonstrated. At least insofar as how we humans are capable of measuring the concept called "time."

I'm not really sure where a god or anything theological would come in or have anything to do with this, either.

Smileycat
04-15-2011, 10:44 AM
We already know time travel is impossible.

No one has come back to tell us they're from the future.

And, frankly, I doubt people from the future are any better at keeping secrets than we are today.

Well, John Titor says he was from our future. Lots of people don't believe he was genuine, while others swear his predictions were on the money. He may have hit the mark on some, but he also missed quite a few so far. So, I don't know that I believe him. Have you heard of him? (See http://www.johntitor.com/)

kuwisdelu
04-15-2011, 10:47 AM
It should be noted that whether time travel is possible and whether humans will ever be capable of it are entirely separate issues. It'd be cool if we could manage it, of course. But there are lots of things that are possible that we can't or don't do for practical reasons.

not_HarryS
04-15-2011, 10:48 AM
Eh, this doesn't really convince me of anything. It's already pretty much accepted that general relativity is incomplete, and there are new theories that even gravity is only an emergent phenomenon rather than an actual force. Which — on a sidenote — makes me think it would be interesting if time is similar in that regard. But I don't see any rigorous justification for concluding anything at all from this.

Besides which, it depends what is meant by "time travel." Are we talking about going back in time? Because traveling forward in time has already pretty much been demonstrated. At least insofar as how we humans are capable of measuring the concept called "time."

I'm not really sure where a god or anything theological would come in or have anything to do with this, either.

Do you have any more info on gravity as an emergent phenomenon as opposed to an actual force? I'm not even entirely sure what that means, so I'd love to read more about it.

Thanks :)

/derail

kuwisdelu
04-15-2011, 10:50 AM
Do you have any more info on gravity as an emergent phenomenon as opposed to an actual force? I'm not even entirely sure what that means, so I'd love to read more about it.

Thanks :)

/derail

Here (http://arstechnica.com/science/news/2011/04/is-gravity-a-result-of-thermodynamics.ars)'s where I saw it. It makes sense in some ways, but it's far from being accepted or proven, of course.

Zoombie
04-15-2011, 10:56 AM
Hi, Zoombie. I just want to understand what you're saying. Do you think that if time travel were possible and the Big Bang is THE theory of how we started, free will would be questionable?

I think some things are preordained, so to speak. But I do think we have choices to make which can deeply affect our lives, too.

Thanks for your opinion.

If time travel were possible, then it would mean that - in a sense - things that are going to happen will have already happened. If you can change the past, or travel into alternate futures, you're just traveling between dimensions.

If everything has already happened, then there is no free will, as all choices have already been made.

And as someone who likes making choices, I'm not a big fan of predestination in any of it's forms, whether its via time travel or providence.

Smileycat
04-15-2011, 11:12 AM
Eh, this doesn't really convince me of anything. It's already pretty much accepted that general relativity is incomplete, and there are new theories that even gravity is only an emergent phenomenon rather than an actual force. Which — on a sidenote — makes me think it would be interesting if time is similar in that regard. But I don't see any rigorous justification for concluding anything at all from this.

Besides which, it depends what is meant by "time travel." Are we talking about going back in time? Because traveling forward in time has already pretty much been demonstrated. At least insofar as how we humans are capable of measuring the concept called "time."

I'm not really sure where a god or anything theological would come in or have anything to do with this, either.

I also think general relativity isn't all it was hoped to be.

Time travel means just that - back and forward. Linear time, although seemingly easy to measure, has some peculiarities about it. Have you ever read any of Jenny Randles' books? I have Time Storms: The Amazing Evidence of Time Warps, Space Rifts and Time Travel. Amazing true stories. You can read a few incidents in this amazon book excerpt page - http://www.amazon.co.uk/Time-Storms-Amazing-Evidence-Travel/dp/0749922427#reader_0749922427.

I believe we need to account for ALL incidents, not throw out the ones that don't fit in with what we think it means.

As far as God goes, I always try to tie everything together. That's just me. I think that quote from Revelation is much deeper than people realize, and I think it implies something about time.

Smileycat
04-15-2011, 11:14 AM
It should be noted that whether time travel is possible and whether humans will ever be capable of it are entirely separate issues. It'd be cool if we could manage it, of course. But there are lots of things that are possible that we can't or don't do for practical reasons.

I agree.

LOG
04-15-2011, 11:18 AM
If time and space are one, then why would we be able move through space but not time?
Or is that too simplistic a way of looking at it?

Smileycat
04-15-2011, 11:28 AM
If time travel were possible, then it would mean that - in a sense - things that are going to happen will have already happened. If you can change the past, or travel into alternate futures, you're just traveling between dimensions.

If everything has already happened, then there is no free will, as all choices have already been made.

And as someone who likes making choices, I'm not a big fan of predestination in any of it's forms, whether its via time travel or providence.

I see. What about the theory of multiverses? See http://en.wikipedia.org/wiki/Multiverse. Every possibility already exists, and we may just jump from one to another, like in the old Sliders program about travelling between multiverses? It aired on Fox, then the Sci-fi channel. There was some freedom of choice depicted in that show.

The question for me is (about multiverses) "Is there a limit to the amount of realities that any choice could produce?" Does a new universe appear simply by thinking about it? Then, wouldn't that tie in with the theory that we are living in a computer simulation? See http://www.simulation-argument.com/simulation.html.

Smileycat
04-15-2011, 11:29 AM
If time and space are one, then why would we be able move through space but not time?
Or is that too simplistic a way of looking at it?

Maybe because time is a different dimension? Or maybe we can, but are not able to perceive it in this third dimension?

Zoombie
04-15-2011, 11:30 AM
Really, I'm going to wait until an actual physicst shows up in this thread before I think much more. I just don't have the grounding to say anything more than hobbdlygobbldy and flim flam.

Smileycat
04-15-2011, 11:40 AM
Really, I'm going to wait until an actual physicst shows up in this thread before I think much more. I just don't have the grounding to say anything more than hobbdlygobbldy and flim flam.

Okay, Zoombie... Passes the Tylenol.

DrZoidberg
04-15-2011, 11:44 AM
Time travel is quite possible. I've done it many times. Here's a demonstration. I will now travel one second into the future

*poof*

...and now we're here... in the FUTURE!!!

third person
04-15-2011, 11:45 AM
Time is but a unit of measurement for the human experience. It is always now.

Smileycat
04-15-2011, 11:50 AM
Time travel is quite possible. I've done it many times. Here's a demonstration. I will now travel one second into the future

*poof*

...and now we're here... in the FUTURE!!!

You're awfully cute. See third person's reply.

kuwisdelu
04-15-2011, 12:01 PM
I also think general relativity isn't all it was hoped to be.

I think that's a somewhat more subjective way of putting it. General relativity is a very good theory, just like Newtonian physics is a very good theory. Simply because they're incomplete doesn't make them any less good for explaining a large amount of what we see.


Time travel means just that - back and forward. Linear time, although seemingly easy to measure, has some peculiarities about it.

Going forward in time at different rates is fairly easy and has been demonstrated. Traveling at speeds of a significant enough fraction of the speed of light will result in time passing slower locally, which is a result that has been measured and can be repeated.


Have you ever read any of Jenny Randles' books? I have Time Storms: The Amazing Evidence of Time Warps, Space Rifts and Time Travel. Amazing true stories. You can read a few incidents in this amazon book excerpt page - http://www.amazon.co.uk/Time-Storms-Amazing-Evidence-Travel/dp/0749922427#reader_0749922427.

I believe we need to account for ALL incidents, not throw out the ones that don't fit in with what we think it means.

I haven't, but I checked out the link. It looks like mostly anecdotes. I'm not the kind of person to dismiss those kinds of things out of hand, but I hardly think they should be given the credence of repeatable results and phenomena.


As far as God goes, I always try to tie everything together. That's just me. I think that quote from Revelation is much deeper than people realize, and I think it implies something about time.

I'm not much of a theist, in the traditional sense, so I rarely think about that kind of thing.


If time and space are one, then why would we be able move through space but not time?
Or is that too simplistic a way of looking at it?


Maybe because time is a different dimension? Or maybe we can, but are not able to perceive it in this third dimension?

Time is traditionally thought of as the fourth dimension. In special relativity, we use four-vectors to represent vectors in space and time. We are indeed capable of traveling forward in time at different rates (though it takes an obscene amount of energy to do it enough to matter to human perception).

If we could travel backward in time, it would violate causality. And furthermore, because of space time geometry, it would imply the ability to travel at faster than the speed of light. From a practical standpoint, this is impossible because the consequences of special relativity mean it will take more and more energy to continue accelerating the faster you go, and asymptotically, it would take an infinite amount of energy to reach the speed of light and, i.e., travel back in time. Theoretically, there's nothing that prevents time travel if you can jump across that speed of light border somehow.


Really, I'm going to wait until an actual physicst shows up in this thread before I think much more. I just don't have the grounding to say anything more than hobbdlygobbldy and flim flam.

I only have a minor in physics, and I haven't read much new research in a while, so I'm pretty out of the loop here, too.


Time is but a unit of measurement for the human experience. It is always now.

For scientific measurements, we usually use more reliable measurements for time, such as the oscillations of atoms or other particles than something as fallible as "the human experience."

shelleyo
04-15-2011, 12:09 PM
Well, John Titor says he was from our future. Lots of people don't believe he was genuine, while others swear his predictions were on the money. He may have hit the mark on some, but he also missed quite a few so far. So, I don't know that I believe him. Have you heard of him? (See http://www.johntitor.com/)

He wouldn't miss any if he really came back from the future. His prediction of a civil war in America that would start in 2004 and build through 2015, for instance. Total rubbish, hasn't happened. If he lived it already, he could not possibly be mistaken. So just based on that one, he's a fraud. The rest really don't matter after a doozy like that, do they?

Even a time-traveler with a crap memory wouldn't remember a civil war that lasted 11 years that didn't happen. :P


Shelley

kuwisdelu
04-15-2011, 12:31 PM
He wouldn't miss any if he really came back from the future. His prediction of a civil war in America that would start in 2004 and build through 2015, for instance. Total rubbish, hasn't happened. If he lived it already, he could not possibly be mistaken. So just based on that one, he's a fraud. The rest really don't matter after a doozy like that, do they?

Even a time-traveler with a crap memory wouldn't remember a civil war that lasted 11 years that didn't happen. :P

Well you have to consider that merely existing in a time you don't belong could have unforeseen effects that could result in massive changes in the timeline.

I mean, I still think he's full of crap. Just saying.

Celia Cyanide
04-15-2011, 01:07 PM
Well, fuck...there goes my plans for the weekend...

Smileycat
04-15-2011, 01:15 PM
I think that's a somewhat more subjective way of putting it. General relativity is a very good theory, just like Newtonian physics is a very good theory. Simply because they're incomplete doesn't make them any less good for explaining a large amount of what we see.
I have no problem with that.


Going forward in time at different rates is fairly easy and has been demonstrated. Traveling at speeds of a significant enough fraction of the speed of light will result in time passing slower locally, which is a result that has been measured and can be repeated.
Sources? (Want to see exactly what you mean.)


I haven't, but I checked out the link. It looks like mostly anecdotes. I'm not the kind of person to dismiss those kinds of things out of hand, but I hardly think they should be given the credence of repeatable results and phenomena.
These are experiences people had. They do not qualify as scientific method data, of course.


I'm not much of a theist, in the traditional sense, so I rarely think about that kind of thing.
I am just trying to tie that in. I have a puzzle brain.


Time is traditionally thought of as the fourth dimension. In special relativity, we use four-vectors to represent vectors in space and time. We are indeed capable of traveling forward in time at different rates (though it takes an obscene amount of energy to do it enough to matter to human perception).
Some say 4th dimension, while others say each different universe is a different dimension, because they may actually occupy the same space. So if the idea of a multiverse means, everything is happening now, just in a different dimension, maybe we should go back to the Vedic way of thinking. They have always believed in a multiverse - http://www.bibliotecapleyades.net/vida_alien/vidaalien_signtimes08a.htm (http://www.bibliotecapleyades.net/vida_alien/vidaalien_signtimes08a.htm). As far as your statement that " We are indeed capable of traveling forward in time at different rates," I will need to see some examples, please.


If we could travel backward in time, it would violate causality. And furthermore, because of space time geometry, it would imply the ability to travel at faster than the speed of light. From a practical standpoint, this is impossible because the consequences of special relativity mean it will take more and more energy to continue accelerating the faster you go, and asymptotically, it would take an infinite amount of energy to reach the speed of light and, i.e., travel back in time. Theoretically, there's nothing that prevents time travel if you can jump across that speed of light border somehow.
Some say that, but how do we truly know that? There is no evidence or proof. No repeatable experiment to accumulate data for the scientific method, which is required by science.


I only have a minor in physics, and I haven't read much new research in a while, so I'm pretty out of the loop here, too.
I'm not a scientist.


For scientific measurements, we usually use more reliable measurements for time, such as the oscillations of atoms or other particles than something as fallible as "the human experience."
As third dimensional beings, we measure everything using materials of our dimension.

Smileycat
04-15-2011, 01:16 PM
He wouldn't miss any if he really came back from the future. His prediction of a civil war in America that would start in 2004 and build through 2015, for instance. Total rubbish, hasn't happened. If he lived it already, he could not possibly be mistaken. So just based on that one, he's a fraud. The rest really don't matter after a doozy like that, do they?

Even a time-traveler with a crap memory wouldn't remember a civil war that lasted 11 years that didn't happen. :P


Shelley

Hi, Shelly. I agree with kuwisdelu on this.

Smileycat
04-15-2011, 01:18 PM
Well, fuck...there goes my plans for the weekend...

Hi, Celia! Let's go drinking instead! :e2drunk:

kuwisdelu
04-15-2011, 02:23 PM
Sources? (Want to see exactly what you mean.)

According to special relativity, time dilation occurs between two reference frames that are traveling at relativistic speeds with respect to each other. (I.e., going really, really fast.) If you go fast enough, locally, time will slow down, meaning if you go fast enough, you can essentially travel to the future.

The Hafele-Keating experiment from 1972 showed this effect by putting atomic clocks on jets and flying them in opposite directions around the Earth, and then comparing their times to a control atomic clock on the ground. Naturally, because we're only capable of going so fast, the effect is only traveling a few nanoseconds into the "future," but there was a noticeable and measurable effect that — within the limits of measurement error — agreed with the theory. This is a repeatable experiment.



Some say 4th dimension, while others say each different universe is a different dimension, because they may actually occupy the same space. So if the idea of a multiverse means, everything is happening now, just in a different dimension, maybe we should go back to the Vedic way of thinking. They have always believed in a multiverse - http://www.bibliotecapleyades.net/vida_alien/vidaalien_signtimes08a.htm (http://www.bibliotecapleyades.net/vida_alien/vidaalien_signtimes08a.htm). As far as your statement that " We are indeed capable of traveling forward in time at different rates," I will need to see some examples, please.

Eh, this confusion is mainly the result of different interpretations of the word dimension. A dimension is basically just another coordinate orthogonal to any of your any previous dimensions. However you want to interpret it, time is nothing more than a fourth dimension as far as coordinate systems go, because as far as humans are concerned, I only need four coordinates to describe any even uniquely (after I define a frame of reference, anyway): three in space and one in time.

By the way, if you read that page you linked, the time dilation equation for how time can pass at different rates depending on your reference frame is described about a quarter way down the page.

I don't much like the term "multiverse" since it gets confounded by a lot of people spouting nonsense, but I don't have a problem with the many-worlds interpretation of the collapse of the Schrodinger equation.

Basically, the idea is that the any quantum system is indeterminate until it's measured, and exists in a superposition of multiple states. Something can be alive and dead, or in two places at once, described by a probability distribution, but the actual state isn't determined until it's measured. The indeterminate nature of quantum states until they're measured is also a repeatable experiment. (Google the quantum version of Young's double slit experiment.)

The most widely-accepted interpretation of this probabilistic nature of quantum systems is to take them at face value: they're probability distributions. Just like you don't know whether a coin will land heads or tails until it's landed, you don't know whether a quantum system is in a certain state or not until it's measured. That's sort of the gist of the Copenhagen interpretation of quantum mechanics.

The many-worlds interpretation instead postulates that each possible outcome corresponds to a different universe. This is kind of neat, and since there's no real way of knowing what interpretation is correct yet, I don't have a problem with it. However, lots of people misinterpret it, and believe this means that there's a universe for every possible outcome of the world, history, etc. This isn't true, because the interpretation only applies to quantum systems, and something as complex as, say, the neurochemical interactions in the brain to make a decision, aren't quantum systems. So there isn't going to be a separate universe for every decision you might make, etc.

None of that means "everything is happening now," though, even if the many-worlds interpretation is true. It just means (if it's true) there's a difference universe for each state of a quantum system. You would still have to travel among them linearly, in effect, through time. It would just mean you would have different, branching paths to choose from instead of one path. All of that's a big "if."



Some say that, but how do we truly know that? There is no evidence or proof. No repeatable experiment to accumulate data for the scientific method, which is required by science.

You're right, we don't have any tests for that particular part of the theory, since we don't have nearly enough energy to attempt it. However, it's a mathematical consequence of the rest of special relativity, and we have mountains of data that supports the parts of the theory we can test. That gives strong evidence that the rest of the theory is likely correct as well.



As third dimensional beings, we measure everything using materials of our dimension.

As sarcastic as it may have seemed, Dr Zoidberg was right. We're fourth dimensional beings at least, not third dimensional, because we do travel through time; we just have little control over the rate, and, for the time being, no control over the direction. Though I'm not sure what you're point is here. "The human experience" doesn't really fall neatly into any particular dimension or anything, and isn't really an accurate tool for measuring anything.

On a final note, if we consider the geometry of time like we consider the geometry of space, we could, perhaps, think of time as having a nearly infinite slope. Like a very steep mountain, it's almost impossible to do anything but slide down in one direction. It's been a while since I last did any tensor calculus or dealt with geodesics, but we know from general relativity that things like mass and energy can affect the the geometry of space-time. If time has a constant but nearly-infinite gradient in the direction of the future, it makes sense that all we need to do is find enough energy to alter the local geometry enough to result in a negative gradient for time, toward the past. Which would be consistent with the fact that any world line with a slope less than the speed of light in special relativity is effectively traveling back through time, but doing so would require an infinite amount of energy.

We'd need a lot of energy, of course.

(ETA: Forgive me, real physicists, for where I've screwed up. Like I said, it's been a few years.)

Diana Hignutt
04-15-2011, 02:36 PM
Time is an abstraction, an illusion to make sense of the world around us. Yes, time travel is possible. Look for evidence in my WIP, after it's finished and pubbed, of course.

Torgo
04-15-2011, 04:49 PM
Read an interesting pop-science book once called How to Build a Time Machine which suggested that you could effectively travel in time using our old friends wormholes. Please bear with me as, off the top of my head, I mangle the facts horribly.

The difficulty is that you need a colossal amount of energy to get one to open and then you need to keep it open using exotic matter - that is, stuff that has weird properties like negative mass. And then you probably wouldn't be able to open it wide enough to do anything useful with. (Something in my head is saying "The Casimir Effect", which just sounds really cool - negative energy, or something. It maybe involves rotating mirrors?)

But as far as I remember it has something to do with having two ends of this wormhole, and then shooting one of the ends off at relativistic speeds so it ends up a long, long way away. You could then in theory step through the wormhole and end up instantly at the other side. And somehow this means we can travel in time, because of relativity and junk.

It does solve the "why haven't we met any time travellers" issue, though, because under this theory you can only travel back in time to when you opened the first wormhole. So it's possible we could do this and then suddenly all kinds of people would pile out of it clutching future editions of the Racing Post or something.

Please may I have my PhD now? kthxbai.

Vince524
04-15-2011, 05:14 PM
I hope time travel is possible. Then maybe I could get back the 10 minutes I spent trying to understand what the H E Double Hockey Sticks everyone in this thread was saying.

MattW
04-15-2011, 05:29 PM
"Death is but a window, time is but a door."

- Vigo the Carpathian, the Cruel, the Torturer, the Despised

Rufus Coppertop
04-15-2011, 05:45 PM
Really, I'm going to wait until an actual physicst shows up in this thread before I think much more. I just don't have the grounding to say anything more than hobbdlygobbldy and flim flam.



And I was seriously about to ask you about Lorentz transformations and causality and superluminal stuff! :rant:

Diana Hignutt
04-15-2011, 06:11 PM
There are those that say, once the first time machine is invented, every timetraveller who ever entered a machine in the future will come walking out, one after another ad infinitum.

shelleyo
04-15-2011, 06:15 PM
Well you have to consider that merely existing in a time you don't belong could have unforeseen effects that could result in massive changes in the timeline.

I understand what you're saying, and at the same time I've never understood it, if that makes sense.

If his arrival and presence here changed the timeline, a timeline in which he still exists as a future self, then that "him" would not have ever experienced the war either, because it did not happen and so he could not have experienced it.

I can never wrap my head around the paradox of that, and that leads me to believe that time travel isn't possible, not in any way we can understand.



I mean, I still think he's full of crap. Just saying.

Regardless of the science, yes. After reading about him a bit, I'm confident he's either delusional or an intentional fraud. Probably the latter.

Shelley

muravyets
04-15-2011, 06:43 PM
Read an interesting pop-science book once called How to Build a Time Machine which suggested that you could effectively travel in time using our old friends wormholes. Please bear with me as, off the top of my head, I mangle the facts horribly.

The difficulty is that you need a colossal amount of energy to get one to open and then you need to keep it open using exotic matter - that is, stuff that has weird properties like negative mass. And then you probably wouldn't be able to open it wide enough to do anything useful with. (Something in my head is saying "The Casimir Effect", which just sounds really cool - negative energy, or something. It maybe involves rotating mirrors?)

But as far as I remember it has something to do with having two ends of this wormhole, and then shooting one of the ends off at relativistic speeds so it ends up a long, long way away. You could then in theory step through the wormhole and end up instantly at the other side. And somehow this means we can travel in time, because of relativity and junk.

It does solve the "why haven't we met any time travellers" issue, though, because under this theory you can only travel back in time to when you opened the first wormhole. So it's possible we could do this and then suddenly all kinds of people would pile out of it clutching future editions of the Racing Post or something.

Please may I have my PhD now? kthxbai.
I so desperately want this to be a verbatim quote of the actual paper. :D


There are those that say, once the first time machine is invented, every timetraveller who ever entered a machine in the future will come walking out, one after another ad infinitum.
Oh, gods, then under no circumstances let anyone invent the damned thing.

Torgo
04-15-2011, 06:55 PM
Here's the guy whose book I was imperfectly remembering:
http://www.edge.org/3rd_culture/davies/davies_index.html

The book's a great read, although for all I know it's all cobblers.

Williebee
04-15-2011, 07:18 PM
MOD NOTE: I can't do travel through time, (except for of the one second = one second variety), but I can do travel through space.

Aaaaaand, here we are. :)

Critical Theory

(Yeah, I know the thread was started from a new article. But, as opposed to current events, the discussion is critical thinking about possible events, past and present. SO...)

Thanks, all. Sorry about any turbulence.
-- Williebee

tarcanus
04-15-2011, 07:20 PM
time machine. I accidentally created a



Oh man, did I just ruin all of this threads theories with that? Sorry guys :'(

BunnyMaz
04-15-2011, 07:20 PM
Well, given that the article itself ends with "but it turned out their idea for time travel wouldn't work because of X so we can't afterall", I'd say we're still safe re; time travel.

Speaking as a sort-of physicist (quit degree close to the end due to poverty) who still doesn't fully grasp all this quantum strings crap.


At first, the researchers thought that, if they could build a metamaterial in which light could move in a circle (and so that its mathematical description were identical to particles moving through spacetime), then they could create CTCs.
But when further analyzing the situation, they found restrictions on how light rays could move in the model. Although certain rays could return to their starting points, they would not perceive the correct timelike dimension. In contrast, rays that do perceive this timelike dimension cannot move in circles. The researchers concluded that Nature seems to resist the creation of CTCs, and that time travel - at least in this model - is impossible.

kuwisdelu
04-16-2011, 12:46 AM
Speaking as a sort-of physicist (quit degree close to the end due to poverty) who still doesn't fully grasp all this quantum strings crap.

Not everyone buys string theory anyway, nor do I think it has much to do with time travel. String theorists have had a couple decades to do something interesting, and, IMO, they've failed.

Anyway, if we're just speculating now, I'm out.

ColoradoGuy
04-16-2011, 05:13 AM
I have no idea how this thread ended up in the Lit/Crit room. I'll probably be moving it somewhere else.

small axe
04-16-2011, 09:15 AM
Any "evidence" would probably only "show" whatever one result we see after the collapse of an infinite number of multiverse quantuum possibilities.

Avoiding theology (because those threads inevitably turn ugly, and then everyone gets erased because a few misbehave) we can imagine a multiverse where everything that can happen, does happen, and happens "simultaneously" and regardless of Time or Space or Cause and Effect.

"Free will" could still then be exercised even though "everything is already determined" ... because we might be choosing our trajectory or path (while not choosing a specific outcome).

God or a time-traveller or whatever would be "changeless" if they were transcendent of all the specific Possibilities via being or moving between ALL possibilities.

Omniscient, omnipresent may or may not be Almighty, since being the first two might cause one to be indifferent to being the last.

If we wish to experience and explore ALL ... then there is little reason to select or de-select, cause or prevent any specific reality (that would be denying the ALLness)

There, I just started a New Religion: send me Money and Nookie! :D (But respecting the ALL, I also understand why there may be some unfortunate reality where you fail to send me my rightful Money and Nookie. Rats.

okay, don't send me rats ... I specifically renounce the reality where folks send me rats as a sign of cultic devotion. :Sun:

Smileycat
04-16-2011, 10:22 PM
kuwisdelu -

I owe you a post, but I don't want to take the short way out. I have limited time, so I'll get back to you when I have more time. Basically, I think we misunderstand where each other is coming from. See you later, okay?

Nick Blaze
04-16-2011, 11:01 PM
If time travel was possible and we stumbled upon it, World War III would be upon us. And, the best part of that, is that we could go back in time to try to make it so that WWIII didn't happen! Fancy that.

Skyler
04-17-2011, 01:43 AM
I'm one of the few that believes the past is fixed. That doesn't mean you can't travel back in time, it just means that doing so won't change anything because everything you do in the past has already happened.

Somewhat unsurprisingly I also believe in "divine determinism." I'm one of those Calvinist creeps that believes in both choice and predestination. :evil

With respect to the linked article's conclusions in particular, it's worth noting that the argument assumes that the mathematics of electromagnetic spaces and general relativity are parallel. It doesn't address the fact that general relativity only describes the universe on large scales (quantum mechanics being needed to describe the universe on small scales), and it's not immediately clear how much of an effect (if any) that omission would have on the results of the experiment.

I will look over the article on arXiv at some point, that may have more details than the summary on physorg.com. I don't know yet.

The question about what difference it would make if there was no Big Bang is interesting. For one thing, the passage in Revelations (and, I think, the rest of the Bible) teaches that God is eternal--He has no beginning, no end, and essentially is "outside time." That doesn't hold for the rest of the universe, which had a definite beginning and will have a definite ending.

The question of whether or not there was a "Big Bang" is kind of a moot one. We know that the universe came into existence at some point. (There are a vast array of scientific evidences and philosophical proofs of this fact.) The real question is what happened--and even that isn't as big of a question as it may seem.

The mathematical models of the Big Bang are based largely upon extrapolations from our universe as it exists now, so whether or not it accurately describes what happened in the past (which is a discussion I don't think we need to go into here), it should correlate to reality today. Therefore, experiments conducted on the basis of those mathematical models should produce valid conclusions, assuming their other premises are valid as well.

I think the last line of the physorg.com article is key here:


The researchers concluded that Nature seems to resist the creation of CTCs, and that time travel - at least in this model - is impossible.

Pistol Whipped Bee
04-17-2011, 01:47 AM
I wouldn't jump so fast on the bandwagon spray painted "We already know time travel is impossible."

No one can explain deja-vu. Everytime scientists think they know something some 14 year old nerdy twerp (You guys are way cool) comes along and blows everyone out of the water. We don't even understand ourselves. Our adacity at thinking we can KNOW anything about something so much bigger than us is laughable.

whistlelock
04-17-2011, 11:33 AM
Well, John Titor says he was from our future. Lots of people don't believe he was genuine, while others swear his predictions were on the money. He may have hit the mark on some, but he also missed quite a few so far. So, I don't know that I believe him. Have you heard of him? (See http://www.johntitor.com/)

titor is a con man. and crazy.

if I came from the future I'd have a way better website. and a lot more money because I'd know about the GREATEST ECONOMIC COLLAPSE since the Great Depression, and know which stocks to buy and when to sell.

Xelebes
04-17-2011, 11:52 AM
No one can explain deja-vu.

I've never had an unexplainable deja vu. :|

Satori1977
04-17-2011, 08:15 PM
Well, John Titor says he was from our future. Lots of people don't believe he was genuine, while others swear his predictions were on the money. He may have hit the mark on some, but he also missed quite a few so far. So, I don't know that I believe him. Have you heard of him? (See http://www.johntitor.com/)

I don't know/understand enough about physics to comment on most of this thread. But this website is a bunch of BS. First of all, when was the last time it was even updated. I see "predictions" from 2001 and 2004. And nothing I read ever came to pass. So we are in the middle of a huge civil war right now? Russia has attacked us? Where have I been??

FOTSGreg
04-17-2011, 11:46 PM
Okay, let me try to get my head around this.

A time traveller goes back in time, it does not matter particularly when. He could go back a second or a trillion years.

The very act of his traveling in time changes time. If he arrives at a particular time period it doesn't matter. Time progresses forward in a standard fashion and he finds that time does NOT progress as he remembers.

In essence, the time traveler has placed himself outside of the "time stream" by traveling in time. Nothing he can do will have effects on how the stream flows anymore than if he'd tossed a pebble into a river.

He can't kill his grandfather before he was conceived, he can't save the Titanic, he can't save Kennedy, etc. Time happens exactly as it's supposed to with the traveller standing to one side frustrated and incapable of doing anything.

Pistol Whipped Bee
04-17-2011, 11:54 PM
I've never had an unexplainable deja vu. :|

I noticed you didn't explain it. :/

Maxx
04-18-2011, 12:05 AM
According to this article at physorg.com: http://www.physorg.com/news/2011-04-big-simulated-metamaterial-impossible.html

An excerpt:

I wonder if this means it would be possible if there was no Big Bang? For those of you who studied the Bible at all, God is defined as "I am the Alpha and the Omega, the Beginning and the End,: says the Lord, "who is and who was and who is to come, the Almighty," in Revelation 1:8.

May I have your opinion?

I looked at the original article and off-hand -- I don't see why closed time-like curves are considered necessary for time travel. I myself don't find the idea of time-travel particularly plausible since it seems to amount to simple faster than light travel in ordinary space time, ie if you assume there is a place to go then both it and you are in ordinary space time so you are just going there so as to arrive before light from there could reach you. If you assume there is "some other place to go" then again, is travel to some other place, not time travel.
I thought closed time like curves defined event horizons? Maybe those are trapped surfaces (which sounds like the same thing).

kuwisdelu
04-18-2011, 12:38 AM
The question of whether or not there was a "Big Bang" is kind of a moot one. We know that the universe came into existence at some point. (There are a vast array of scientific evidences and philosophical proofs of this fact.) The real question is what happened--and even that isn't as big of a question as it may seem.

The mathematical models of the Big Bang are based largely upon extrapolations from our universe as it exists now, so whether or not it accurately describes what happened in the past (which is a discussion I don't think we need to go into here), it should correlate to reality today. Therefore, experiments conducted on the basis of those mathematical models should produce valid conclusions, assuming their other premises are valid as well.

We can use the sheer size of the universe to our advantage to coax evidence about the past from the present. Light that is currently reaching us from distant stars today originated from those stars billions of years ago, so examining the light from distant stars essentially allows us to look back billions of years into the past to the state of the universe as it was back then.

We're able to find evidence for our current theories about the Big Bang and inflation by mapping the distribution of matter and energy in the universe, and comparing how well it aligns with the distribution that would result if our current theories are true. Similarly, the cosmic microwave background radiation that permeates the universe agrees with our theories as well.

There are still holes here and there, of course, but by-and-large most of our understanding seems to agree with our observations.

Xelebes
04-18-2011, 01:08 AM
I noticed you didn't explain it. :/

Deja vu is the feeling of being forewarned that comes to be with a happening that answers it. Our feelings are, for the most part, grounded by what has happened to us and our keenness to look forward. However, some of that cannot be kept in mind and therefore we forget, but when it arises again we can feel like it has not happened before and be left dumbfounded by what feels like something has happened again.

Skyler
04-18-2011, 01:37 AM
Deja vu is the feeling of being forewarned that comes to be with a happening that answers it. Our feelings are, for the most part, grounded by what has happened to us and our keenness to look forward. However, some of that cannot be kept in mind and therefore we forget, but when it arises again we can feel like it has not happened before and be left dumbfounded by what feels like something has happened again.

What? I'm lost.

Deja vu is the sense that something has happened before, isn't it?

And doesn't it happen when they make a change in the Matrix?

Xelebes
04-18-2011, 01:41 AM
What? I'm lost.

Deja vu is the sense that something has happened before, isn't it?

And doesn't it happen when they make a change in the Matrix?

Exactly what I said. You were thinking it was going to happen in some form or another at some time before the happening occurs and when that happening happens, you get frightened by it. That is deja vu.

Smileycat
04-18-2011, 01:43 AM
According to special relativity, time dilation occurs between two reference frames that are traveling at relativistic speeds with respect to each other. (I.e., going really, really fast.) If you go fast enough, locally, time will slow down, meaning if you go fast enough, you can essentially travel to the future.



The Hafele-Keating experiment from 1972 showed this effect by putting atomic clocks on jets and flying them in opposite directions around the Earth, and then comparing their times to a control atomic clock on the ground. Naturally, because we're only capable of going so fast, the effect is only traveling a few nanoseconds into the "future," but there was a noticeable and measurable effect that — within the limits of measurement error — agreed with the theory. This is a repeatable experiment.
Would this hold up on a Quantum level? Over a vast distance level? Within black holes? I think this might just be an effect of linear time at the scale in which it was tested. We have no way to test this on a large scale, and, until we do, I am reserving judgment as to whether or not this is true for all distances and possible scales. I'm not sure I made myself clear as to what I mean here. Do you get me here?



Eh, this confusion is mainly the result of different interpretations of the word dimension. A dimension is basically just another coordinate orthogonal to any of your any previous dimensions. However you want to interpret it, time is nothing more than a fourth dimension as far as coordinate systems go, because as far as humans are concerned, I only need four coordinates to describe any even uniquely (after I define a frame of reference, anyway): three in space and one in time.


By the way, if you read that page you linked, the time dilation equation for how time can pass at different rates depending on your reference frame is described about a quarter way down the page.

I don't much like the term "multiverse" since it gets confounded by a lot of people spouting nonsense, but I don't have a problem with the many-worlds interpretation of the collapse of the Schrodinger equation.

Basically, the idea is that the any quantum system is indeterminate until it's measured, and exists in a superposition of multiple states. Something can be alive and dead, or in two places at once, described by a probability distribution, but the actual state isn't determined until it's measured. The indeterminate nature of quantum states until they're measured is also a repeatable experiment. (Google the quantum version of Young's double slit experiment.)

The most widely-accepted interpretation of this probabilistic nature of quantum systems is to take them at face value: they're probability distributions. Just like you don't know whether a coin will land heads or tails until it's landed, you don't know whether a quantum system is in a certain state or not until it's measured. That's sort of the gist of the Copenhagen interpretation of quantum mechanics.

The many-worlds interpretation instead postulates that each possible outcome corresponds to a different universe. This is kind of neat, and since there's no real way of knowing what interpretation is correct yet, I don't have a problem with it. However, lots of people misinterpret it, and believe this means that there's a universe for every possible outcome of the world, history, etc. This isn't true, because the interpretation only applies to quantum systems, and something as complex as, say, the neurochemical interactions in the brain to make a decision, aren't quantum systems. So there isn't going to be a separate universe for every decision you might make, etc.

None of that means "everything is happening now," though, even if the many-worlds interpretation is true. It just means (if it's true) there's a difference universe for each state of a quantum system. You would still have to travel among them linearly, in effect, through time. It would just mean you would have different, branching paths to choose from instead of one path. All of that's a big "if."
I have read that some scientists and laymen alike believe that these universes exist at the same time, even though they take place in different linear time (e.g. Jurassic period as opposed to our now).

Anecdotal story: A teacher goes on vacation to Sedona, Arizona with a bunch of other professionals. They are walking about in the treeless area not far from their hotel. The tour guide explains what they are looking at. The trip is pleasant so far. All of a sudden, there is sort of nudge and a change in atmosphere. Out of the left side of her eye, she sees... wait for it... a dinosaur, grazing on tree branches that do not exist on her trip. She turns to look at the dinosaur as it turns to look at her. Then, just as quickly as it appeared, there was a change in atmosphere again and the dinosaur and trees disappear. I heard this story second hand from the tour guide.

I have also heard that there are 11 dimensions, and that the multiverses represented within this conglomerate of universes are multiples of any of the 11 dimensions, thus (in my interpretation) making for an infinite amount of universes of each basic dimension (which is why I referred to them as being infinite dimensions). I hope I explained that better. See Michio Kaku's explanation here: http://184.106.231.42/ideas/24629.



You're right, we don't have any tests for that particular part of the theory, since we don't have nearly enough energy to attempt it. However, it's a mathematical consequence of the rest of special relativity, and we have mountains of data that supports the parts of the theory we can test. That gives strong evidence that the rest of the theory is likely correct as well.
I have doubts about that, because at least one of the Space Shuttle missions showed that basic fluid mechanic laws did not all act as expected while the shuttle was in orbit miles above Earth (don't ask me which one - I spent enough time looking for the mission, but it was not recent). What would happen to all the other physics laws if tested on different scales?



As sarcastic as it may have seemed, Dr Zoidberg was right. We're fourth dimensional beings at least, not third dimensional, because we do travel through time; we just have little control over the rate, and, for the time being, no control over the direction. Though I'm not sure what you're point is here. "The human experience" doesn't really fall neatly into any particular dimension or anything, and isn't really an accurate tool for measuring anything.


On a final note, if we consider the geometry of time like we consider the geometry of space, we could, perhaps, think of time as having a nearly infinite slope. Like a very steep mountain, it's almost impossible to do anything but slide down in one direction. It's been a while since I last did any tensor calculus or dealt with geodesics, but we know from general relativity that things like mass and energy can affect the the geometry of space-time. If time has a constant but nearly-infinite gradient in the direction of the future, it makes sense that all we need to do is find enough energy to alter the local geometry enough to result in a negative gradient for time, toward the past. Which would be consistent with the fact that any world line with a slope less than the speed of light in special relativity is effectively traveling back through time, but doing so would require an infinite amount of energy.

We'd need a lot of energy, of course.

(ETA: Forgive me, real physicists, for where I've screwed up. Like I said, it's been a few years.)

Re: Us living in a 4th dimensional world as opposed to a 3rd dimensional world - see the Michio Kaku link above. If you'll note, Kaku says we exist in the 3rd dimension, not the 4th, as you stated. Other scientists also say the sae thing. Therefore, I am not sure where you are coming from. Could you expound on that? Since we don't really understand time fully, we are not living in a time-based dimension. Being in a third dimensional world, we fully understand what the 1st, 2nd and 3rd dimensions represent. We do not fully understand the 4th dimension, so we don't live in its world.

There is a lot we do not understand, kuwisdelu.

Smileycat
04-18-2011, 01:52 AM
Read an interesting pop-science book once called How to Build a Time Machine which suggested that you could effectively travel in time using our old friends wormholes. Please bear with me as, off the top of my head, I mangle the facts horribly.

The difficulty is that you need a colossal amount of energy to get one to open and then you need to keep it open using exotic matter - that is, stuff that has weird properties like negative mass. And then you probably wouldn't be able to open it wide enough to do anything useful with. (Something in my head is saying "The Casimir Effect", which just sounds really cool - negative energy, or something. It maybe involves rotating mirrors?)

But as far as I remember it has something to do with having two ends of this wormhole, and then shooting one of the ends off at relativistic speeds so it ends up a long, long way away. You could then in theory step through the wormhole and end up instantly at the other side. And somehow this means we can travel in time, because of relativity and junk.

It does solve the "why haven't we met any time travellers" issue, though, because under this theory you can only travel back in time to when you opened the first wormhole. So it's possible we could do this and then suddenly all kinds of people would pile out of it clutching future editions of the Racing Post or something.

Please may I have my PhD now? kthxbai.

Wormholes were used as transportation in the Star Trek series, Star Wars movies and even in Donnie Darko. It has some supporters in science, too. See http://en.wikipedia.org/wiki/Wormhole.

Can't award you with a Ph. D., since I am not affiliated with a university conferring these doctorate degrees. :tongue

Smileycat
04-18-2011, 02:06 AM
I have no idea how this thread ended up in the Lit/Crit room. I'll probably be moving it somewhere else.

My head is spinning, much like a wormhole as it eats stars.

Skyler
04-18-2011, 02:07 AM
Exactly what I said. You were thinking it was going to happen in some form or another at some time before the happening occurs and when that happening happens, you get frightened by it. That is deja vu.

I don't know if that's what you said or not, but that makes a lot more sense. Thanks.

Smileycat
04-18-2011, 02:07 AM
titor is a con man. and crazy.

if I came from the future I'd have a way better website. and a lot more money because I'd know about the GREATEST ECONOMIC COLLAPSE since the Great Depression, and know which stocks to buy and when to sell.

I do not believe he was really from the future myself.

Smileycat
04-18-2011, 02:24 AM
I looked at the original article and off-hand -- I don't see why closed time-like curves are considered necessary for time travel. I myself don't find the idea of time-travel particularly plausible since it seems to amount to simple faster than light travel in ordinary space time, ie if you assume there is a place to go then both it and you are in ordinary space time so you are just going there so as to arrive before light from there could reach you. If you assume there is "some other place to go" then again, is travel to some other place, not time travel.
I thought closed time like curves defined event horizons? Maybe those are trapped surfaces (which sounds like the same thing).

It has to do with the Theory of General Relativity. I am not a physicist, so don't ask me. I have my doubts about general relativity anyway.

kuwisdelu
04-18-2011, 03:10 AM
Would this hold up on a Quantum level? Over a vast distance level? Within black holes? I think this might just be an effect of linear time at the scale in which it was tested. We have no way to test this on a large scale, and, until we do, I am reserving judgment as to whether or not this is true for all distances and possible scales. I'm not sure I made myself clear as to what I mean here. Do you get me here?

Special relativity is pretty well tested in both cases. It's General relativity that has trouble with the quantum scale.

I'm not sure what you mean by "an effect of linear time."



I have read that some scientists and laymen alike believe that these universes exist at the same time, even though they take place in different linear time (e.g. Jurassic period as opposed to our now).

It's pretty much all speculation at this point, so I'm not going to debate it one way or the other.


Anecdotal story: A teacher goes on vacation to Sedona, Arizona with a bunch of other professionals. They are walking about in the treeless area not far from their hotel. The tour guide explains what they are looking at. The trip is pleasant so far. All of a sudden, there is sort of nudge and a change in atmosphere. Out of the left side of her eye, she sees... wait for it... a dinosaur, grazing on tree branches that do not exist on her trip. She turns to look at the dinosaur as it turns to look at her. Then, just as quickly as it appeared, there was a change in atmosphere again and the dinosaur and trees disappear. I heard this story second hand from the tour guide.

I don't give much credence to anecdotes unless I'm in a conspiratorial mood, which isn't generally true when I'm discussing physics.


I have also heard that there are 11 dimensions, and that the multiverses represented within this conglomerate of universes are multiples of any of the 11 dimensions, thus (in my interpretation) making for an infinite amount of universes of each basic dimension (which is why I referred to them as being infinite dimensions). I hope I explained that better. See Michio Kaku's explanation here: http://184.106.231.42/ideas/24629.

The 11 dimensions are a mathematical consequence of a certain kind of string theory. Lots of physicists like string theory, but so far, it has yet to provide a shred of evidence in its support. It's mathematically pretty elegant, though, and does pretty much agree with all of our other experimentally-supported theories so far. String theorists have yet to offer any testable hypotheses. But it's an internally consistent theory that agrees with a lot of current phenomena — just no better than anything else, so far.

You're in fine company to buy into string theory, since it's pretty popular among physicists, but I'm reserving my judgment until they can offer something of more substance than an elegant mathematical framework. There are physicists in both camps.

But as you point out later, there's a lot we don't know, and this is one of them. I wouldn't go making any conclusions based on hypotheses that can't be tested yet.



I have doubts about that, because at least one of the Space Shuttle missions showed that basic fluid mechanic laws did not all act as expected while the shuttle was in orbit miles above Earth (don't ask me which one - I spent enough time looking for the mission, but it was not recent). What would happen to all the other physics laws if tested on different scales?

Fluid mechanics is a very different kind of physics than regular mechanics, E&M, particle physics, cosmology, etc. I don't really know much about it, since it never interested me much.

Most of our other theories are pretty rigorously tested at the particle level in labs and if there were any disagreement on the macro scale, we'd notice it from observations on the rest of the universe.

And I can say that with confidence, because there is a major case of disagreement, and we know it because of exactly that — General relativity cannot be reconciled with quantum mechanics in their current forms. It's one of the biggest ongoing problems to be solved in modern physics.




Re: Us living in a 4th dimensional world as opposed to a 3rd dimensional world - see the Michio Kaku link above. If you'll note, Kaku says we exist in the 3rd dimension, not the 4th, as you stated. Other scientists also say the sae thing. Therefore, I am not sure where you are coming from. Could you expound on that? Since we don't really understand time fully, we are not living in a time-based dimension. Being in a third dimensional world, we fully understand what the 1st, 2nd and 3rd dimensions represent. We do not fully understand the 4th dimension, so we don't live in its world.

I only mean to say that we do experience time. We do travel through it, just at a nearly constant pace, in one direction. We must have some existence in it, then. But obviously, it's very limited, since we have little control over it. If we were solely third dimensional beings, then we would only exist for a single moment and disappear.


There is a lot we do not understand, kuwisdelu.

I never said there wasn't.

Smileycat
04-18-2011, 09:52 AM
Special relativity is pretty well tested in both cases. It's General relativity that has trouble with the quantum scale.
As far as I'm concerned, none of the laws, including Special Relativity or General Relativity jibes with all the other accepted theories, like Quantum Physics.


I'm not sure what you mean by "an effect of linear time."
I think linear time as we know it in a third dimensional way doesn't behave the way time would if we were actually existing in its own dimension, which probably IS in the fourth dimension.

Let me explain. Say you are a lower dimensional being (like a virus). A third dimensional being enters your world and you see it in a second dimensional way, not a third dimensional way, simply because you can see length and width BUT NOT DEPTH. Did I explain that okay?



It's pretty much all speculation at this point, so I'm not going to debate it one way or the other.
That's how I feel about a lot of this stuff. Although man thinks he understands what is happening, he does not.

For example, in the last 5 years or so, there have been conflicting observations about the speed of expansion of our universe. (See http://www.google.com/search?q=expansion+in+universe+slowing+down&sourceid=ie7&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe= (http://www.google.com/search?q=expansion+in+universe+slowing+down&sourceid=ie7&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe)) Like the HGTV home repair show where the owners fail to make the renovations properly, so are our scientists in Over Your Head (name of the show).



I don't give much credence to anecdotes unless I'm in a conspiratorial mood, which isn't generally true when I'm discussing physics.
It was not offered as scientific empirical data, but as a story a reputable person offered to tie in the shared space/different dimension idea. BTW, other people did feel the change in atmosphere, but did not witness the dino/trees. It would have been interesting had someone captured some of the air to test, but, of course, no one had a sterile jar handy.



The 11 dimensions are a mathematical consequence of a certain kind of string theory. Lots of physicists like string theory, but so far, it has yet to provide a shred of evidence in its support. It's mathematically pretty elegant, though, and does pretty much agree with all of our other experimentally-supported theories so far. String theorists have yet to offer any testable hypotheses. But it's an internally consistent theory that agrees with a lot of current phenomena — just no better than anything else, so far.

You're in fine company to buy into string theory, since it's pretty popular among physicists, but I'm reserving my judgment until they can offer something of more substance than an elegant mathematical framework. There are physicists in both camps.

But as you point out later, there's a lot we don't know, and this is one of them. I wouldn't go making any conclusions based on hypotheses that can't be tested yet.
I almost never buy into any theory, including this one. But, Michio Kaku is more accepted worldwide than you or me.



Fluid mechanics is a very different kind of physics than regular mechanics, E&M, particle physics, cosmology, etc. I don't really know much about it, since it never interested me much.

Most of our other theories are pretty rigorously tested at the particle level in labs and if there were any disagreement on the macro scale, we'd notice it from observations on the rest of the universe.

And I can say that with confidence, because there is a major case of disagreement, and we know it because of exactly that — General relativity cannot be reconciled with quantum mechanics in their current forms. It's one of the biggest ongoing problems to be solved in modern physics.
Okay about Fluid Mechanics, but the laws are based on experiments, just like any other law.

Observations of the universe have turned up unexpected surprises, so I dont fully trust them either. If the law has to do with Earth, like Newtonian Physics does, I tend to accept it FOR EARTH, and maybe for our immediate surroundings, and sun type. But when it comes to neutron stars, black holes, etc., nope.

There are so many oddities that are ignored by scientists because they tend to do that. They tend to drop/ignore data that does not conform to whatever theory they are trying to prove. I listen and may repeat what they say as interesting, but I almost never buy it totally.



I only mean to say that we do experience time. We do travel through it, just at a nearly constant pace, in one direction. We must have some existence in it, then. But obviously, it's very limited, since we have little control over it. If we were solely third dimensional beings, then we would only exist for a single moment and disappear.

See my blurb about it above. Also, I happen to believe the dimension of time is involved in many other dimensions, including the 1st and 2nd. Is there a time cutoff? If something last for ANY length of time, isn't time involved? Your explanation, although I can see where you're coming from, doesn't quite make sense to me.

DrZoidberg
04-18-2011, 02:46 PM
I've found a helpful metaphor to help me sort out what time travel means. Time is a function of movement. Energy through space. This world is basically inside an explosion (The Big Bang). To travel back in time we'd have to push back all that energy in a controlled manner back so some earlier place in space, using a power source that would negate and override the energy of the outward expansion of this explosion. How would we control it? Even if we ignore the fiscal and practical limitations there are profound philosophical problems. If we push this matter back to earlier positions, isn't it just a different kind of now? How would it be the past even if it physically resembles it?

Maxx
04-18-2011, 04:24 PM
I've found a helpful metaphor to help me sort out what time travel means. Time is a function of movement. Energy through space. This world is basically inside an explosion (The Big Bang). To travel back in time we'd have to push back all that energy in a controlled manner back so some earlier place in space, using a power source that would negate and override the energy of the outward expansion of this explosion. How would we control it? Even if we ignore the fiscal and practical limitations there are profound philosophical problems. If we push this matter back to earlier positions, isn't it just a different kind of now? How would it be the past even if it physically resembles it?

Well that's the strict reversal of events kind of time travel. I assume a trapped (if not closed surface) would have you travel into the future in order to wind up in the past.

movieman
04-18-2011, 06:56 PM
As far as I'm concerned, none of the laws, including Special Relativity or General Relativity jibes with all the other accepted theories, like Quantum Physics.

There is no inconsistency between quantum mechanics and special relativity: we just rarely use relativistic quantum mechanics because the equations become extremely difficult to solve and in most cases in normal life we don't run into relativistic effects.

Maxx
04-18-2011, 07:14 PM
There is no inconsistency between quantum mechanics and special relativity: we just rarely use relativistic quantum mechanics because the equations become extremely difficult to solve and in most cases in normal life we don't run into relativistic effects.

All QM events are modified by relativistic effects. In the everyday world these amount to minor corrections (eg. the Lamb Shift), but they are inherent in all QM interactions.

As for difficult to solve: as far as I know, not even QM has been solved explicitly beyond the simplest cases. For example, electron transitions in molecules are known from lab measurements, not calculated from the Schoedinger eq.

Relativistic effects of course do come up in fairly common events, for example, pair production (electrons and positrons from gamma rays or even lasers):

http://pra.aps.org/abstract/PRA/v8/i3/p1582_1

Smileycat
04-18-2011, 11:28 PM
There is no inconsistency between quantum mechanics and special relativity: we just rarely use relativistic quantum mechanics because the equations become extremely difficult to solve and in most cases in normal life we don't run into relativistic effects.

Well, I guess the word inconsistency might be misleading. There is no hard empirical eviddence that I know of that brings the two together. Is there?

Smileycat
04-18-2011, 11:32 PM
I've found a helpful metaphor to help me sort out what time travel means. Time is a function of movement. Energy through space. This world is basically inside an explosion (The Big Bang). To travel back in time we'd have to push back all that energy in a controlled manner back so some earlier place in space, using a power source that would negate and override the energy of the outward expansion of this explosion. How would we control it? Even if we ignore the fiscal and practical limitations there are profound philosophical problems. If we push this matter back to earlier positions, isn't it just a different kind of now? How would it be the past even if it physically resembles it?

'Time is a function of movement.' I am not getting this. Nor am I getting the 'push back all that energy' bit with regard to overriding 'the energy of the expansion of the explosion.' (Big Bang explosion?) Nor do I understand your 'different kinf of now' reference.

Are you trying to work out what time travel could be?

Maxx
04-18-2011, 11:39 PM
Well, I guess the word inconsistency might be misleading. There is no hard empirical eviddence that I know of that brings the two together. Is there?

Special relativity is basic to all formulations of quantum mechanics since Dirac (ie since 1927, all of quantum theory has had special relativity built into it). The hard empirical evidence is essentially everything observed since 1927 that made sense in terms of quantum mechanics or any of its associated theories (QED, QCD etc.)

Torgo
04-19-2011, 12:19 AM
'Time is a function of movement.' I am not getting this.

As far as my very limited understanding of current physics goes - and I would really love it if someone would take the time to point out my inevitable errors, because this whole thing fascinates me - spacetime can most easily be understood as a single manifold. It's a single surface - a four-dimensional one - that we're moving about on.

A ball is three-dimensional - an easy surface to imagine. Let's try to imagine a four-dimensional surface: frankly I can't. But it has a geometry and maths to describe it, and the maths seems to work, just like Euclid works for triangles. And if you look carefully at the maths, you appear in some cases to be able to take weird shortcuts.

There are things like closed timelike curves, for example. You're traveling across this surface. For the curve - the steps of your journey - to be timelike, there's a timelike interval between each step. A timelike interval means that there is enough time between each step for the first to have a causal relationship to the second. Point A affects point B, which affects point C, and so on.

The weirdness comes in when it turns that out in highly weird situations, you can take a journey which ends up with point C being behind point A, and thus affecting it. The curve is closed; it's a circle.

I can imagine setting off around the equator and arriving 'behind' my starting position. I think this is the same sort of thing? Except much more complicated. The conditions under which such journeys are possible seem to involve infinitely-long spinning cylinders, and other impractical things like that.

Treating spacetime this way seems to make a bunch of things easier, but it does lead to these weird conclusions. As far as I can tell, either our current theory is correct and time-travel is remotely possible (but amazingly hard), or there's some wrinkle that we haven't noticed yet.

Sarpedon
04-19-2011, 12:47 AM
Let me explain. Say you are a lower dimensional being (like a virus). A third dimensional being enters your world and you see it in a second dimensional way, not a third dimensional way, simply because you can see length and width BUT NOT DEPTH. Did I explain that okay?


Huh? How is a virus not a three dimensional thing? And how would a more than 3 dimensional being 'enter' a 3 dimensional worldspace?

I think certain analogies have been stretched too far. It is important to remember that analogies are not reality. They help illustrate reality.

As far as the closed-time loops and wormholes, I believe that the idea of wormholes exists as a consequence to the idea that space is "curved." An analogy is the surface of the earth. We perceive it as flat because of our smallness compared to it. Of course, if you go far enough you arrive back where you started. Space may be curved in an analogous way, in that it may loop back on itself, or it may be an 'open curve' which though still curved, does not fold back on itself, or it may be 'flat' in which case it is limitless and uniform in every direction. If it is 'curved' then the possibility of 'worm holes' is opened. These would be short cuts between different parts of the curve. Their creation is through a particularly arcane physics subject called 'quantum tunneling,' as far as I can make out.

Whether the possibility of space worm holes leads to the possibility of time worm holes is beyond my ken, but I suspect it is very doubtful. Presumably, if it were possible, time would have to be curved, just like space would have to be, hence smilecat's saying that it is dependent on time being on a 'loop.'

movieman
04-19-2011, 01:10 AM
As for difficult to solve: as far as I know, not even QM has been solved explicitly beyond the simplest cases.

But the relativistic form of Schrodinger's Equation makes the non-relativistic form look simple.

And yes, obviously there are relativistic effects even at very low velocities, but they're so minor until you get close to the speed of light that there's no need to bother with them if you can actually solve the equation when you don't include them.

Hallen
04-19-2011, 02:38 AM
According to this article at physorg.com: http://www.physorg.com/news/2011-04-big-simulated-metamaterial-impossible.html

An excerpt:

I wonder if this means it would be possible if there was no Big Bang? For those of you who studied the Bible at all, God is defined as "I am the Alpha and the Omega, the Beginning and the End,: says the Lord, "who is and who was and who is to come, the Almighty," in Revelation 1:8.

May I have your opinion?

If the big bang (or whatever it was that created this universe) did not happen, then it's a moot point because this universe wouldn't be and if there was a universe, then it wouldn't necessarily be like this one.

As for the Revelations statement, make of it what you will. Either God created everything and will destroy everything and is unending or Alpha represents food and Omega represents poop. You could read it either way.

Smileycat
04-19-2011, 03:10 AM
If the big bang (or whatever it was that created this universe) did not happen, then it's a moot point because this universe wouldn't be and if there was a universe, then it wouldn't necessarily be like this one.

As for the Revelations statement, make of it what you will. Either God created everything and will destroy everything and is unending or Alpha represents food and Omega represents poop. You could read it either way.

Hi, Hallen. Why do you say,"If the big bang (or whatever it was that created this universe) did not happen, then it's a moot point because this universe wouldn't be and if there was a universe, then it wouldn't necessarily be like this one"? I don't understand what you're getting at here.

Smileycat
04-19-2011, 03:17 AM
Huh? How is a virus not a three dimensional thing? And how would a more than 3 dimensional being 'enter' a 3 dimensional worldspace?

I think certain analogies have been stretched too far. It is important to remember that analogies are not reality. They help illustrate reality.

As far as the closed-time loops and wormholes, I believe that the idea of wormholes exists as a consequence to the idea that space is "curved." An analogy is the surface of the earth. We perceive it as flat because of our smallness compared to it. Of course, if you go far enough you arrive back where you started. Space may be curved in an analogous way, in that it may loop back on itself, or it may be an 'open curve' which though still curved, does not fold back on itself, or it may be 'flat' in which case it is limitless and uniform in every direction. If it is 'curved' then the possibility of 'worm holes' is opened. These would be short cuts between different parts of the curve. Their creation is through a particularly arcane physics subject called 'quantum tunneling,' as far as I can make out.

Whether the possibility of space worm holes leads to the possibility of time worm holes is beyond my ken, but I suspect it is very doubtful. Presumably, if it were possible, time would have to be curved, just like space would have to be, hence smilecat's saying that it is dependent on time being on a 'loop.'

To answer your dimensional question, see http://wiki.answers.com/Q/What_is_the_second_dimension. A piece of paper (2nd), a thin thread (1st). A virus is like that, is it not? We even occupy the same space, since the human body contains viruses and bacteria that would qualify as lower dimensional beings.

As far as wormholes, etc., we have no proof, no scientific data, so we can talk about these things as long as we keep that in mind.

Hallen
04-19-2011, 04:09 AM
The event we call the big bang is not understood, but some event created the universe. If a different event happened, something other than what created our universe, then we'd end up with a different universe than what we have now -- call it universe B. If we lived in B, then the experiment you reference would conform to a different set of physics and the results would be different than what we got this time.

If, however, the only way to create a universe is with a big bang, and what you get is simply a differently distributed universe (where the stuff goes) but essentially the same physics, then that experiment would imply exactly the same thing it implies now -- time travel backwards is not possible.

I know this stuff is very existential, and I am by no means a physics expert. It's just my perspective on the logic of it all. :)

Smileycat
04-19-2011, 12:26 PM
The event we call the big bang is not understood, but some event created the universe. If a different event happened, something other than what created our universe, then we'd end up with a different universe than what we have now -- call it universe B. If we lived in B, then the experiment you reference would conform to a different set of physics and the results would be different than what we got this time.

If, however, the only way to create a universe is with a big bang, and what you get is simply a differently distributed universe (where the stuff goes) but essentially the same physics, then that experiment would imply exactly the same thing it implies now -- time travel backwards is not possible.

I know this stuff is very existential, and I am by no means a physics expert. It's just my perspective on the logic of it all. :)

Okay, I think I understand. Please correct me if I am wrong. You are saying there is no other possibility other than the Big Bang (that started our Universe)?

There are those who would disagree with you. Although Big Bang is the number one theory at this time, it is not the only possibility. See http://blogs.discovermagazine.com/cosmicvariance/2007/04/27/how-did-the-universe-start/. Excerpt:

Many scenarios have been put forward among the “specific” category. We have of course the “quantum cosmology” program, that tries to write down a wavefunction of the universe; the classic example is the paper by Hartle and Hawking (http://prola.aps.org/abstract/PRD/v28/i12/p2960_1). There have been many others, including recent investigations within loop quantum gravity (http://arxiv.org/abs/gr-qc/0601085). Although this program has led to some intriguing results, the silent majority or physicists seems to believe that there are too many unanswered questions about quantum gravity to take seriously any sort of head-on assault on this problem. There are conceptual puzzles: at what point does spacetime make the transition from quantum to classical? And there are technical issues: do we really think we can accurately model the universe with only a handful of degrees of freedom, crossing our fingers and hoping that unknown ultraviolet effects don’t completely change the picture? It’s certainly worth pursuing, but very few people (who are not zero-gravity tourists (http://dorigo.wordpress.com/2007/04/27/steven-hawking-at-large/)) think that we already understand the basic features of the wavefunction of the universe.

At a slightly less ambitious level (although still pretty darn ambitious, as things go), we have attempts to “smooth out” the singularity in some semi-classical way. Aguirre and Gratton (http://arxiv.org/abs/astro-ph/0111191) have presented a proof by construction that such a universe is conceivable; essentially, they demonstrate how to take an inflating spacetime, cut it near the beginning, and glue it to an identical spacetime that is expanding the opposite direction of time. This can either be thought of as a universe in which the arrow of time reverses at some special midpoint, or (by identifying events on opposite sides of the cut) as a one-way spacetime with no beginning boundary. In a similar spirit, Gott and Li (http://arxiv.org/abs/astro-ph/9712344) suggest that the universe could “create itself,” springing to life out of an endless loop of closed timelike curves. More colorfully, “an inflationary universe gives rise to baby universes, one of which turns out to be itself.”

And of course, you know that there are going to be ideas based on string theory. For a long time Veneziano and collaborators have been studying what they dub the pre-Big-Bang (http://arxiv.org/abs/hep-th/9802057) scenario. This takes advantage of the scale-factor duality of the stringy cosmological field equations: for every cosmological solution with a certain scale factor, there is another one with the inverse scale factor, where certain fields are evolving in the opposite direction. Taken literally, this means that very early times, when the scale factor is nominally small, are equivalent to very late times, when the scale factor is large! I’m skeptical that this duality survives to low-energy physics, but the early universe is at high energy, so maybe that’s irrelevant. A related set of ideas have been advanced by Steinhardt, Turok, and collaborators, first as the ekpyrotic (http://arxiv.org/abs/hep-th/0103239) scenario and later as the cyclic universe (http://arxiv.org/abs/hep-th/0111098) scenario. Both take advantage of branes and extra dimensions to try to follow cosmological evolution right through the purported Big Bang singularity; in the ekpyrotic case, there is a unique turnaround point, whereas in the cyclic case there are an infinite number of bounces stretching endlessly into the past and the future.


That is why I asked if it wasn't possible that the Bible got something right in that our Universe always existed (I view God as the Universe).

What do you think?

Sarpedon
04-19-2011, 04:55 PM
Analogies, smileycat, a piece of paper is like a two dimensional thing. It is not a two dimensional thing, because it has a thickness. Just a very small thickness. Don't mistake the analogy for the thing itself.

Likewise, a virus is very small. But it has length, width and height. Therefore it is a three dimensional thing.

Torgo
04-19-2011, 05:20 PM
That is why I asked if it wasn't possible that the Bible got something right in that our Universe always existed (I view God as the Universe).

What do you think?

I think it's an irrelevant question. So what if the Bible got something right? It doesn't mean that anything or everything else it avers is true.

Abraham Lincoln, Vampire Hunter gets some things right about Lincoln, and a whole lot of things wrong.

In this case, you would be relying on a metaphorical identification of God with the Universe, which was probably never intended by any of the various authors of the Bible, and seems to contradict Genesis (in which God and his creation appear to be explicitly separate.)

Maxx
04-19-2011, 06:34 PM
What do you think?

Gott's name resembles the Herr Gott of German discursive practice. Li's name resembles a the sounding of a Chinese ideogram associated with a cosmic principle.

Perhaps more frightening (at least for the Afrika Abteilung in North Africa in 1942). In August 1942, the 8th Army was on the verge of being commanded by Gott Himself or at least his Avatar Lieutant-General William Henry Ewart Gott CB, CBE, DSO and bar, MC.



http://upload.wikimedia.org/wikipedia/commons/thumb/7/74/Lieutenant_General_Gott.jpg/250px-Lieutenant_General_Gott.jpg (http://www.absolutewrite.com/wiki/File:Lieutenant_General_Gott.jpg)

DrZoidberg
04-19-2011, 07:27 PM
'Time is a function of movement.' I am not getting this.


Yeah... you just showed the limits of my simple explanation. There's no way to explain this that doesn't get complicated fast. A short non-simplified explanation is this. Time is relative. Things travelling at a faster speed will compared to things standing still will age slower. See... time is a function of movement/speed? I don't know how to explain this simpler. This is not intuitive at all.




Nor am I getting the 'push back all that energy' bit with regard to overriding 'the energy of the expansion of the explosion.'


Any given time can be seen as only being a specific layout of matter in space. If we'd move the matter back to any earlier point in time we'd then have travelled back in time in a way. This universe we have has it's origins in a singularity that exploded. That means that we've physically moved in space outwards from the centre. This needs (at least partly) to be reversed somehow for time travel.



(Big Bang explosion?) Nor do I understand your 'different kinf of now' reference.


What if you moved back home to your parents house. But you wanted it to look exactly like it was when you lived there. You redecorate your house to make it look exactly the same. You had a tree in the garden that now is huge. So you physically take the molecules in the tree, and you rearrange them to make it identical to when you lived there. You even take the bleached paints in the curtains and bring back colour molecules to make them brighter. You similarly de-age the oak floors. You even change the carbon-14 amounts in the wood. You change it in such a way that no scientific lab could ever tell the difference.

If you'd really want to go overboard you could change the molecules in your body and your parents. You could rearrange the neurons in your brain to match the neuronal pattern of your childhood. You'd be a child again.

Ok, here's the question; have you travelled back in time? Talking physics, this is what it means to exist in an earlier time. Does the fact that you've manipulated matter like this disqualify this from ever counting as time-travel? If yes, then time-travel is impossible. But this simply a philosophical question. Down to semantics. There's no scientific reason why it wouldn't be theoretically possible.

Jamesaritchie
04-19-2011, 07:29 PM
If the big bang (or whatever it was that created this universe) did not happen, then it's a moot point because this universe wouldn't be and if there was a universe, then it wouldn't necessarily be like this one.

As for the Revelations statement, make of it what you will. Either God created everything and will destroy everything and is unending or Alpha represents food and Omega represents poop. You could read it either way.


Actually, there's more and more doubt in scientific circles abut whether or not there actually was a big bang.

As someone once said, "We don't begin to know what we don't know, and we know only half of what we think we know."

glutton
04-19-2011, 07:42 PM
If God exists he could easily time travel. Or step outside time, or move a quintillion times faster than light, or negate the stupid laws of relativity (which never really make sense to me no matter how many times or ways it's explained).

Heck, maybe there are some below God-level beings (angels? 4th or higher dimensional beings? comic book style cosmics? :D) that can do those things and just operate on a level far above our notice...

Torgo
04-19-2011, 07:47 PM
Actually, there's more and more doubt in scientific circles abut whether or not there actually was a big bang.

Really? My impression was that there was less and less. But then, I am a layman.

Smileycat
04-19-2011, 07:48 PM
Analogies, smileycat, a piece of paper is like a two dimensional thing. It is not a two dimensional thing, because it has a thickness. Just a very small thickness. Don't mistake the analogy for the thing itself.

Likewise, a virus is very small. But it has length, width and height. Therefore it is a three dimensional thing.

I didn't Sarpedon (is that a type of dinosaur?). I was the one saying 'like,' wasn't I?

Sarpedon
04-19-2011, 07:52 PM
If you understand the analogy, why do you persist in calling a virus a less than three dimensional thing?

And no, an iguanodon is a kind of dinosaur. Sarpedon was a character in the iliad, and is depicted on the vase I use as an avatar.

Smileycat
04-19-2011, 07:53 PM
I think it's an irrelevant question. So what if the Bible got something right? It doesn't mean that anything or everything else it avers is true.

Abraham Lincoln, Vampire Hunter gets some things right about Lincoln, and a whole lot of things wrong.

In this case, you would be relying on a metaphorical identification of God with the Universe, which was probably never intended by any of the various authors of the Bible, and seems to contradict Genesis (in which God and his creation appear to be explicitly separate.)

Okay, now I'm confused as to what you mean. First you say, "So what if the Bible got something right?" Then you say I am "relying on a metaphorical identification of God with the Universe, which was probably never intended by any of the various authors of the Bible, and seems to contradict Genesis (in which God and his creation appear to be explicitly separate.)"

Do you think God (which is the Universe in my view) always existed, or that God just popped out of nothing, like people who believe in the Big Bang? That's what I am asking.

Smileycat
04-19-2011, 07:55 PM
Gott's name resembles the Herr Gott of German discursive practice. Li's name resembles a the sounding of a Chinese ideogram associated with a cosmic principle.

Perhaps more frightening (at least for the Afrika Abteilung in North Africa in 1942). In August 1942, the 8th Army was on the verge of being commanded by Gott Himself or at least his Avatar Lieutant-General William Henry Ewart Gott CB, CBE, DSO and bar, MC.

I was not being frivolous.

Torgo
04-19-2011, 07:57 PM
I didn't Sarpedon (is that a type of dinosaur?). I was the one saying 'like,' wasn't I?

Sarpedon: Trojan badass, slain by Patroclus, IIRC.

I'm not sure you're being consistent about viruses etc, given that upthread you stated that


We even occupy the same space, since the human body contains viruses and bacteria that would qualify as lower dimensional beings.

To me it looks like you said that 2-dimensional entities could occupy the same space we do, and that viruses and bacteria were examples of them?

Maxx
04-19-2011, 07:59 PM
Really? My impression was that there was less and less. But then, I am a layman.

Who can imagine what somebody might mean by saying there were doubts about the Big Bang in scientific circles?

As far as I know, there's not much doubt about the basic model that explains primordial element abundance and the cosmic microwave background radiation in that those both seem to require an early dense universe that expanded and cooled. There are a lot of different models of the big bang that seek to fit together different parameters (eg. dark matter and the cosmic constant), but all models I can think of that are part of active research have some sort of early, dense phase and some sort of cooling and expansion.
You might say the role of the big bang and the realm it explains has changed, but there is still a major role for some kind of big bang sequence of events.

Maxx
04-19-2011, 08:02 PM
I was not being frivolous.

Gott is a serious person. All Gotts are serious people. Some Gotts may be major deities in their spare time, as in
Herr Gott.

Maxx
04-19-2011, 08:03 PM
Do you think God (which is the Universe in my view) always existed, or that God just popped out of nothing, like people who believe in the Big Bang? That's what I am asking.

I believe in the Big Bang and I didn't pop out of nothing. My mother claims I was born into this world just like a real boy.

Torgo
04-19-2011, 08:04 PM
Okay, now I'm confused as to what you mean. First you say, "So what if the Bible got something right?" Then you say I am "relying on a metaphorical identification of God with the Universe, which was probably never intended by any of the various authors of the Bible, and seems to contradict Genesis (in which God and his creation appear to be explicitly separate.)"

Do you think God (which is the Universe in my view) always existed, or that God just popped out of nothing, like people who believe in the Big Bang? That's what I am asking.

1) I don't think God exists, so let's get that out of the way; asking if God popped out of nothing is meaningless.

2) You stated that the Bible said that God is Alpha and Omega, always existing; that some people believe the universe always existed; that you identify God with the universe; so does that mean the Bible was right?

3) I say it doesn't mean anything in particular if the Bible is right about any one particular thing.

4) I think your identification of God with God's Creation (the Universe) is contrary to the Bible, which makes a clear distinction.

5) I don't have any particular problem believing the Big Bang narrative, no, given that before the Big Bang there was no before, and no nothing, and no causality.

glutton
04-19-2011, 08:12 PM
So if there was absolutely nothing before the Big Bang, why did it occur? (Serious question, don't remember the details of the theory even though I must have learned it in school before)

Astronomer
04-19-2011, 08:12 PM
I'm one of the few that believes the past is fixed. That doesn't mean you can't travel back in time, it just means that doing so won't change anything because everything you do in the past has already happened.

Somewhat unsurprisingly I also believe in "divine determinism." I'm one of those Calvinist creeps that believes in both choice and predestination. :evil
Me too! On all counts! You're the first I've encountered who agrees with me on these points.

What has happened has always happened. And what will happen has always will happened.

AND we have free will. We are making the universe what it is by all the choices we make.

The universe is like a plank of wood. If you could exist outside the universe, you'd see that one of its dimensions is time. You can cut into any point into its time dimension with your saw, essentially accessing any point in time just as easily as you can access any point along the plank's length. (Heh! :)) Nothing is fluid, everything is fixed, in a solid structure, including events fixed in time.

Don't be fooled by our severely limited perspective of time. Our ability to see only the present, and not time's entire length as a pan-dimensional carpenter would, compels us to think of the future as something that is yet to be. I personally believe that the future (and past) is as fixed and established as any other dimension.

We like to think of ourselves as actors on a stage, with the ability to improvise. But we are more like characters in a novel, existing on all pages simultaneously, but unable to see what happens 100 pages down the road.

But we still make the universe what it is by the choices we make. Causality still rules the day. Just because all the choices we make can all be seen at once from a different perspective doesn't mean we don't make them freely.

Maxx
04-19-2011, 08:24 PM
So if there was absolutely nothing before the Big Bang, why did it occur? (Serious question, don't remember the details of the theory even though I must have learned it in school before)

The usual model is that there was some sort of higher, more symmetric state, maybe with more dimensions and that, that symmetry (ie overall sameness), fluctuated (as well it might since nothing maintained that higher state of total non-being), generating an inflationary field (sometimes identified with the classic standard Higgs in the old days) that expanded at many, many times the speed of light. And the rest is history.

Smileycat
04-19-2011, 08:57 PM
If you understand the analogy, why do you persist in calling a virus a less than three dimensional thing?

And no, an iguanodon is a kind of dinosaur. Sarpedon was a character in the iliad, and is depicted on the vase I use as an avatar.

For the illustration. It helps one conceptualize things better.

But, to be honest, I have been thinking about this a bit recently. Let me ask you these questions. Can you see an atom with your naked eye? No, you cannot. Why is that? Because it is too small. Does it being too small qualify it to be from another dimension? I don't know, but maybe. We can only see them as individuals or in small groups or in their structures using an electron microscope.

Well, it ended in 'don,' as in Amygdalodon. I read the Iliad a long, long time ago and don't remember the character Sarpedon. (embarassed smilie - http://www.absolutewrite.com/forums/images/icons/icon11.gif )

Sarpedon
04-19-2011, 10:21 PM
But, to be honest, I have been thinking about this a bit recently. Let me ask you these questions. Can you see an atom with your naked eye? No, you cannot. Why is that? Because it is too small. Does it being too small qualify it to be from another dimension? I don't know, but maybe. We can only see them as individuals or in small groups or in their structures using an electron microscope.



Here's a link to an image of a molecule. http://nickyskye.blogspot.com/2011/03/single-molecules-stunning-image-love.html

And I'm sorry, you aren't understanding. A two dimensional object, if one were to actually exist, would have NO thickness. Not a very small thickness, not an invisible to the naked eye thickness, but none whatsoever. Atoms have thickness.

And there is no 'from' another dimension. A dimension is not a place. You cannot go and visit the fifth dimension any more than you can visit 'width'. It's not a place, its a description.

The only reason that this whole thing came up in the first place is when scientists observed that some physics problems work out better mathematically if you assumed more dimensions than 4. Whether that means the other dimensions actually exist is debatable.

The pop culture interpretation of the situation has about as much to do with science as the movie Caligula has to do with actual history.

Torgo
04-19-2011, 10:24 PM
But, to be honest, I have been thinking about this a bit recently. Let me ask you these questions. Can you see an atom with your naked eye? No, you cannot. Why is that? Because it is too small. Does it being too small qualify it to be from another dimension? I don't know, but maybe.

Dude, I begin to suspect you of pulling our legs at this point.

kuwisdelu
04-19-2011, 10:45 PM
Smileycat, a lot of your "doubts" are about things scientists have pretty thoroughly tested, and not in the limited settings you seem to believe they did. For example, your suggestion that Newtonian physics is only based on Earth and may not apply to other systems is pretty ridiculous; it's just as valid a limiting case on a neutron star as it is on Earth. Hell, it's a valid limiting case even for black holes until you get close enough for general relativity and quantum mechanics to kick in. There are still a lot of problems and controversies in science, and it's great to question and speculate about those, but some of this stuff we've known for decades or even centuries.


And there is no 'from' another dimension. A dimension is not a place. You cannot go and visit the fifth dimension any more than you can visit 'width'. It's not a place, its a description.

You mean the English dub of Dragonball Z lied to me??!?

Next you'll tell me they actually just died. O_O

Sarpedon
04-19-2011, 10:51 PM
Apparently, in fiction when someone says 'going to another dimension' they mean 'a parallel universe that is separated from ours by a short distance in one of the less usual dimensions.' At least thats according to wiki.

Maxx
04-20-2011, 12:01 AM
Dude, I begin to suspect you of pulling our legs at this point.

Yeah, the "if invisible then other dimension" would apply to things around the corner or in other rooms or in the refrigerator when the refrigerator door is closed and you aren't in the refrigerator. Other dimensions would pop up whenever you weren't looking.

Smileycat
04-20-2011, 03:00 AM
I believe in the Big Bang and I didn't pop out of nothing. My mother claims I was born into this world just like a real boy.
okat. nice to know.

Smileycat
04-20-2011, 03:01 AM
1) I don't think God exists, so let's get that out of the way; asking if God popped out of nothing is meaningless.

2) You stated that the Bible said that God is Alpha and Omega, always existing; that some people believe the universe always existed; that you identify God with the universe; so does that mean the Bible was right?

3) I say it doesn't mean anything in particular if the Bible is right about any one particular thing.

4) I think your identification of God with God's Creation (the Universe) is contrary to the Bible, which makes a clear distinction.

5) I don't have any particular problem believing the Big Bang narrative, no, given that before the Big Bang there was no before, and no nothing, and no causality.

We're not coming from the same place. I think you are not getting me.

Smileycat
04-20-2011, 03:02 AM
So if there was absolutely nothing before the Big Bang, why did it occur? (Serious question, don't remember the details of the theory even though I must have learned it in school before)

I kind of agree with you.

Smileycat
04-20-2011, 03:03 AM
Really? My impression was that there was less and less. But then, I am a layman.


James is right. I posted alternatives earlier. Must have missed that.

Smileycat
04-20-2011, 03:13 AM
Here's a link to an image of a molecule. http://nickyskye.blogspot.com/2011/03/single-molecules-stunning-image-love.html

And I'm sorry, you aren't understanding. A two dimensional object, if one were to actually exist, would have NO thickness. Not a very small thickness, not an invisible to the naked eye thickness, but none whatsoever. Atoms have thickness.

And there is no 'from' another dimension. A dimension is not a place. You cannot go and visit the fifth dimension any more than you can visit 'width'. It's not a place, its a description.

The only reason that this whole thing came up in the first place is when scientists observed that some physics problems work out better mathematically if you assumed more dimensions than 4. Whether that means the other dimensions actually exist is debatable.

The pop culture interpretation of the situation has about as much to do with science as the movie Caligula has to do with actual history.

I think I have read more than you on this subject because there are people out there who compare viruses and bacteria to 1st or 2nd dimensional beings (which is what I did earlier) - I did not make that up. Nevermind atoms and subatomic particles! Perhaps it has to do with perception, I'm not sure.

As far as the dimension thing goes, ditto. You haven't done your reading. I already posted an article by Michio Kaku.

I only used pop culture to illustrate an easier to understand possibility. I never said Sliders got it right.

I think it is useless to debate this with you, because, as I have said before, I am asking questions, like everyone else. I am open to suggestion that some things may be possible. And, let's face it, nothing you have said is proven. They're just ideas.

I won't spend any more of my time on this with you. It's just a waste of our time.

Astronomer
04-20-2011, 03:23 AM
I don't think the absence of time travelers from the future is sufficient reason to presume that time travel is impossible.

To expound on the wormhole idea put forth earlier, this is how to build a time machine:



Build a wormhole.
Put one of the wormhole openings aboard your near light-speed space ship, and fly it around at near light-speed for a week.
When you get back, one opening of the wormhole will be (almost) one week older than the other. (And the other will be a week younger than the one.)

You're done. Going through the wormhole in one direction will take you a week back in time. Going the other direction will take you a week into the future.

But you will never be able to go back to a time before your wormhole time machine was built. No walking with the dinosaurs, no showing up for Hawking's Time-Traveler Party, and no proving to us 21st century schmucks that the universe allows time travel.

benbradley
04-20-2011, 03:49 AM
omg, all the quantum flapdoodle, I can't bear to look!

Smileycat
04-20-2011, 03:54 AM
Apparently, in fiction when someone says 'going to another dimension' they mean 'a parallel universe that is separated from ours by a short distance in one of the less usual dimensions.' At least thats according to wiki.

agree with that, except that the scientific view is "
The multiverse (or meta-universe, metaverse) is the hypothetical (http://www.absolutewrite.com/wiki/Hypothetical) set of multiple possible universes (http://www.absolutewrite.com/wiki/Universe) (including the historical universe we consistently experience) that together comprise everything that exists (http://www.absolutewrite.com/wiki/Exists): the entirety of space (http://www.absolutewrite.com/wiki/Space), time (http://www.absolutewrite.com/wiki/Time), matter (http://www.absolutewrite.com/wiki/Matter), and energy (http://www.absolutewrite.com/wiki/Energy) as well as the physical laws (http://www.absolutewrite.com/wiki/Physical_law) and constants (http://www.absolutewrite.com/wiki/Physical_constant) that describe them. The term was coined in 1895 by the American philosopher and psychologist William James (http://www.absolutewrite.com/wiki/William_James).[1] (http://www.absolutewrite.com/forums/#cite_note-0) The various universes within the multiverse are sometimes called parallel universes (http://www.absolutewrite.com/wiki/Parallel_universe_(fiction))," also according to Wiki.

Smileycat
04-20-2011, 03:55 AM
omg, all the quantum flapdoodle, I can't bear to look!

Flapdoodle?? I had to look it up!

flap·doo·dle

   [/URL]/ˈflæpˌdudhttp://sp.dictionary.com/dictstatic/dictionary/graphics/luna/thinsp.pngl/ http://sp.dictionary.com/dictstatic/g/d/dictionary_questionbutton_default.gif (http://app.dictionary.com/signup/popup?source=favorites&fnCallback=loginuser&callbackAction=addToFav&domaindest=reference.com) [U]Show Spelled[flap-dood-l] http://sp.dictionary.com/dictstatic/g/d/dictionary_questionbutton_default.gif (http://dictionary.reference.com/help/luna/Spell_pron_key.html) Show IPA
–noun Informal . nonsense; bosh.

Smileycat
04-20-2011, 03:56 AM
I don't think the absence of time travelers from the future is sufficient reason to presume that time travel is impossible.

To expound on the wormhole idea put forth earlier, this is how to build a time machine:



Build a wormhole.
Put one of the wormhole openings aboard your near light-speed space ship, and fly it around at near light-speed for a week.
When you get back, one opening of the wormhole will be (almost) one week older than the other. (And the other will be a week younger than the one.)
You're done. Going through the wormhole in one direction will take you a week back in time. Going the other direction will take you a week into the future.

But you will never be able to go back to a time before your wormhole time machine was built. No walking with the dinosaurs, no showing up for Hawking's Time-Traveler Party, and no proving to us 21st century schmucks that the universe allows time travel.

I refuse to go again!

Astronomer
04-20-2011, 03:57 AM
omg, all the quantum flapdoodle, I can't bear to look!
Isn't "quantum flapdoodle" a bit redundant?

kuwisdelu
04-20-2011, 04:48 AM
I think I have read more than you on this subject because there are people out there who compare viruses and bacteria to 1st or 2nd dimensional beings (which is what I did earlier) - I did not make that up. Nevermind atoms and subatomic particles! Perhaps it has to do with perception, I'm not sure.

Okay, I think the problem is that you may not understand that the word "dimension" can refer to different things depending on the context. It has to do with context; not perception. When physicists talk about dimensions, they mean a particular thing — the x, y, z, and t dimensions of space and time, where x, y, and z are spatial dimensions and t is the time dimension. Physicists use 4-vectors to describe coordinates in space-time. This can be completely different from what a mathematician or a biologist or chemist might mean when they say "dimension." Dimensions basically describe a coordinate system, and there are lots of reasons we use different kinds of coordinate systems in different contexts.

If a chemist or biologist describes a virus as being 2-dimensional, they mean something different from what physicists talk about when they say "dimensions." Let's take the piece of paper as an example. From a practical viewpoint, it's 2-dimensional, since it's third dimension is basically useless for anything I might want to actually do with the paper (unless I want to make origami).

How about molecules? I can describe most molecules by drawing a 2D diagram on a piece of paper showing where the different bonds between atoms go and what kinds of bonds they are. Because most of the time I can uniquely determine what kind of molecule I'm talking about using only 2 dimensions, you might say it's 2 dimensional, but in real space, it still has three dimensions, just like a blueprint of three-dimensional building can uniquely determine how you build it. The blueprint may be 2 dimensional, you may be able to describe the building in 2D space, but the actual building is still 3 dimensional.

Beyond that, I can even uniquely determine any point on Earth using only two dimensions — latitude and longitude. For all practical purposes, I could say Earth is two dimensional. But we all know that's silly.

A dimension can be anything I want it to be. If I have 16 plastic balls on the floor, I could make a square of 4 by 4 balls, and call it 2 dimensional, because my coordinate system uses the size of a ball as part its basis vector, and the rectangle is only 1 ball high. But spatially and temporally (i.e., physic-wise), it would still be three dimensional. I think this is probably what the scientists talking about viruses meant.

A virus is made of molecules is made of atoms. An atom is most definitely three dimensional. Now if we go to elementary particles, you might have something of a point — we can't really say a photon has any width or height or depth. But it still acts and moves in 3D space.


agree with that, except that the scientific view is "
The multiverse (or meta-universe, metaverse) is the hypothetical (http://www.absolutewrite.com/wiki/Hypothetical) set of multiple possible universes (http://www.absolutewrite.com/wiki/Universe) (including the historical universe we consistently experience) that together comprise everything that exists (http://www.absolutewrite.com/wiki/Exists): the entirety of space (http://www.absolutewrite.com/wiki/Space), time (http://www.absolutewrite.com/wiki/Time), matter (http://www.absolutewrite.com/wiki/Matter), and energy (http://www.absolutewrite.com/wiki/Energy) as well as the physical laws (http://www.absolutewrite.com/wiki/Physical_law) and constants (http://www.absolutewrite.com/wiki/Physical_constant) that describe them. The term was coined in 1895 by the American philosopher and psychologist William James (http://www.absolutewrite.com/wiki/William_James).[1] (http://www.absolutewrite.com/forums/#cite_note-0) The various universes within the multiverse are sometimes called parallel universes (http://www.absolutewrite.com/wiki/Parallel_universe_(fiction))," also according to Wiki.

Notice nowhere in there is the word "dimension."

And while I give credence to the multiple worlds interpretation of the wave equation, I still dislike the term "multiverse." It gives too many people the wrong ideas.

Invincibility
04-20-2011, 04:48 AM
Smileycat, you do know about the multiquote function, don't you?

glutton
04-20-2011, 06:02 AM
I kind of agree with you.

I'm not saying that there is a God... I'm agnostic, I don't know if God exists (but I want to believe he does). But some of the theories of physics make less sense to me than the idea of God... not talking about the Big Bang in particular. Relativity... ugh...

kuwisdelu
04-20-2011, 06:09 AM
Relativity... ugh...

Which one?

Both special and general relativity make sense intuitively if they're explained well. On the surface, they're pretty simple. And for calculations, special relativity doesn't really require any more than some basic linear algebra to just about anything with it. The mathematics of general relativity can get pretty insanely difficult, though, which is why it took Einstein so long to finish it.

glutton
04-20-2011, 06:32 AM
Just "why would something moving faster than light cause a time paradox?" And "why couldn't a better theory let something travel that fast without causing a paradox?" That is all...

Astronomer
04-20-2011, 07:35 AM
Just "why would something moving faster than light cause a time paradox?" And "why couldn't a better theory let something travel that fast without causing a paradox?" That is all...
Two events may occur in one order to one observer, but to another observer in a different reference frame, they could be observed to happen in a different order.

For instance, if two people hit their thumbs with hammers simultaneously, then someone closer to Albert would see him his his thumb before he sees Bernie his his thumb, since light from Albert's thumb-smash would hit his eyes first. Likewise for someone closer to Bernie.

But some events are causal, like shooting an apple with a gun. Since shooting the gun causes the bullet to hit the apple (cause and effect), there is no reference frame in the universe from which the apple could be observed to be hit with the bullet before the gun is fired.

But if you allow information to travel faster than light, then you allow reference frames to exist from which the apple's destruction can be observed before the gun is fired. And any time an effect precedes its cause -- even if it's just in certain reference frames -- then you've established the conditions for a paradox to occur.

As for a better theory to allow superluminal speeds without introducing a paradox, I'm not sure there's a market for that since nothing has been observed to move faster than light that would need explaining in such a theory.

glutton
04-20-2011, 04:11 PM
But if you allow information to travel faster than light, then you allow reference frames to exist from which the apple's destruction can be observed before the gun is fired. And any time an effect precedes its cause -- even if it's just in certain reference frames -- then you've established the conditions for a paradox to occur.

This is what I've heard before but I never get... why would the apple's destruction be observed before the gun is "actually" fired, and not just before the gun is "observed" being fired? That is, even if information about the apple's destruction reaches the observer before light from the gun firing does, wouldn't the gun itself already have been fired; ie. the discrepancy would be more of an optical illusion than a paradox?

Smileycat
04-20-2011, 04:11 PM
Smileycat, you do know about the multiquote function, don't you?
You mean for use here at Absolute? I usually copy the quoted reply to Word and finish it there, then upload it to the reply box. I make some adjustments, etc. I'm messing it up, huh?

Astronomer
04-20-2011, 05:13 PM
This is what I've heard before but I never get... why would the apple's destruction be observed before the gun is "actually" fired, and not just before the gun is "observed" being fired? That is, even if information about the apple's destruction reaches the observer before light from the gun firing does, wouldn't the gun itself already have been fired; ie. the discrepancy would be more of an optical illusion than a paradox?

It's more than observation. The reality you observe is real, even though it's not the same reality observed by someone else. A trumpet player on a railroad flatcar will sound flat as he recedes away from someone on the ground, but sharp to someone ahead of him on the track. Which reality is the real reality? Oddly enough, they both are. You may think that the true reality is that the trumpet player is perfectly on pitch, since that's what an observer on the flatcar would hear. But to the other listeners, he really is flat, and he really is sharp, and their realities can be measured and quantified and are just as valid as the reality observed by the listener on the flatcar.

They are all correct.

Set up the experiment with the apple and gun so that after you see the bullet hit the apple, you can push a button to send an FTL signal to the shooter (be it a person or mechanism) that would stop the gun from being fired. Paradox ensues, and bullets fly around with no guns being fired. Who wants that?

I know it's difficult to abandon the notion that there is one objectively correct reference frame from which you will get the true and correct picture, but that notion just isn't the way the universe works. In fact, there is even no such thing as simultaneity (or even "actualness") in this universe, despite our longstanding acquaintance with that concept.

So enforcement of the speed-of-light limit of the universe is required to keep causality from breaking down. And that's a good thing, because, you know, flying bullets are bad.

Smileycat
04-20-2011, 05:14 PM
Okay, I think the problem is that you may not understand that the word "dimension" can refer to different things depending on the context. It has to do with context; not perception. When physicists talk about dimensions, they mean a particular thing — the x, y, z, and t dimensions of space and time, where x, y, and z are spatial dimensions and t is the time dimension. Physicists use 4-vectors to describe coordinates in space-time. This can be completely different from what a mathematician or a biologist or chemist might mean when they say "dimension." Dimensions basically describe a coordinate system, and there are lots of reasons we use different kinds of coordinate systems in different contexts.

If a chemist or biologist describes a virus as being 2-dimensional, they mean something different from what physicists talk about when they say "dimensions." Let's take the piece of paper as an example. From a practical viewpoint, it's 2-dimensional, since it's third dimension is basically useless for anything I might want to actually do with the paper (unless I want to make origami).

How about molecules? I can describe most molecules by drawing a 2D diagram on a piece of paper showing where the different bonds between atoms go and what kinds of bonds they are. Because most of the time I can uniquely determine what kind of molecule I'm talking about using only 2 dimensions, you might say it's 2 dimensional, but in real space, it still has three dimensions, just like a blueprint of three-dimensional building can uniquely determine how you build it. The blueprint may be 2 dimensional, you may be able to describe the building in 2D space, but the actual building is still 3 dimensional.

Beyond that, I can even uniquely determine any point on Earth using only two dimensions — latitude and longitude. For all practical purposes, I could say Earth is two dimensional. But we all know that's silly.

A dimension can be anything I want it to be. If I have 16 plastic balls on the floor, I could make a square of 4 by 4 balls, and call it 2 dimensional, because my coordinate system uses the size of a ball as part its basis vector, and the rectangle is only 1 ball high. But spatially and temporally (i.e., physic-wise), it would still be three dimensional. I think this is probably what the scientists talking about viruses meant.

A virus is made of molecules is made of atoms. An atom is most definitely three dimensional. Now if we go to elementary particles, you might have something of a point — we can't really say a photon has any width or height or depth. But it still acts and moves in 3D space.

Notice nowhere in there is the word "dimension."

And while I give credence to the multiple worlds interpretation of the wave equation, I still dislike the term "multiverse." It gives too many people the wrong ideas.

I hate this style of reply because it does not nest previous replies.

Okay. As far as I remember, you question my understanding of the word dimension. I question your understanding of that word as well. The quote you said doesn't contain the word 'dimension' was the wrong thing to post.

Go here: http://bigthink.com/ideas/20340 and read that one page. In it Michio Kaku talks about an 11-dimensional multiverse. He says (in another article I posted elsewhere in this thread) that there might be a lot of 3rd dimensional worlds (parallel universes) within the multiverse. In other words, if Sally makes a decision to take a job in computer science programming, she may invent a program that revolutionizes the speed with which medical emergencies are handled, thus saving thousands of lives every week. One of those lives is that of a young woman who will discover the cure for MS. One of those MS patients will, in turn, write a concerto that inspires a politician to actually reform his government and disallow any further lobbying, pay-offs, etc. from taking place. The people will love what he's done and a revolution in every country on Earth will turn this world around, ending the oppression of so many people. A new day dawns and mankind faces good times for a change. All because of Sally. For every possibility that occurs, a new third dimensional parallel universe is created within the multiverse. Following me? That is what I am talking about.

In Professor Kaku's blurb (linked above) he states that the word 'multiverse' is used a lot nowadays.

Torgo
04-20-2011, 05:16 PM
Haven't read the Kaku post but am willing to bet £1M that it doesn't aver that viruses are 2D.

glutton
04-20-2011, 05:33 PM
Set up the experiment with the apple and gun so that after you see the bullet hit the apple, you can push a button to send an FTL signal to the shooter (be it a person or mechanism) that would stop the gun from being fired. Paradox ensues, and bullets fly around with no guns being fired. Who wants that?

How would the FTL signal reach the shooter before the gun is fired? Wouldn't it just reach the shooter before the light from the gun firing reaches the observer? If the signal is 2X the speed of light and the shooter is 8 lightyears away (for example), wouldn't 4 years still have passed since the firing of the gun even if the signal is sent at the same time the gun is fired? Or is there some special property of light that I'm missing? Are you saying that to every observer, the time they see something happen is the "actual" time it happens?

That would definitely be max counterintuitive. Much easier to comprehend and believe in the existence of God... :Shrug:

Maxx
04-20-2011, 06:03 PM
Go here: http://bigthink.com/ideas/20340 and read that one page. In it Michio Kaku talks about an 11-dimensional multiverse. He says (in another article I posted elsewhere in this thread) that there might be a lot of 3rd dimensional worlds (parallel universes) within the multiverse.

I think Kaku would say we live in an effectively 4 dimensional universe (3 space + 1 time dimension).
In the above blurb, the multiverse Kaku describes is a kind of tree of supersymmetries with many big-bang style universes bubbling from it. This would be different from the many-worlds style multiverse since the separate bubbles have separate histories.

Sarpedon
04-20-2011, 06:23 PM
Here's another example: Joe is an astronaut in space. Cosmonaut Dmitry zips by in his spherical, semi-transparent space capsule, travelling at a constant speed. In the center of Dmitry's capsule there's a flashing lightbulb. From Dmitry's point of view, he is at rest, since he's not accellerating (he sees Joe zipping by). The light from the flashing lightbulb arrives simultaneously on all the walls of the capsule. From Joe's point of view, because the capsule is moving, the light from the lightbulb arrives at the back of the capsule before it reaches the front of the capsule, because in the time that it takes the light to reach the walls of the capsule, the capsule has moved.

Events that are simultaneous from one frame of reference are not necessarily simultaneous from another one. This has nothing to do with the amount of time it takes the reflected light to reach the observer. (this example is not original to me, I got it from a physics book, who's name escapes me at the moment)

Maxx
04-20-2011, 06:35 PM
Here's another example: Joe is an astronaut in space. Cosmonaut Dmitry zips by in his spherical, semi-transparent space capsule, travelling at a constant speed. In the center of Dmitry's capsule there's a flashing lightbulb. From Dmitry's point of view, he is at rest, since he's not accellerating (he sees Joe zipping by). The light from the flashing lightbulb arrives simultaneously on all the walls of the capsule. From Joe's point of view, because the capsule is moving, the light from the lightbulb arrives at the back of the capsule before it reaches the front of the capsule, because in the time that it takes the light to reach the walls of the capsule, the capsule has moved.

Events that are simultaneous from one frame of reference are not necessarily simultaneous from another one. This has nothing to do with the amount of time it takes the reflected light to reach the observer. (this example is not original to me, I got it from a physics book, who's name escapes me at the moment)

I'm not so sure that Joe wouldn't just see Dmitri's capsule distorted just enough for the light to arrive at all its surfaces at the same time because Joe sees Dmitri's capsule in terms of a Lorentz contraction.

glutton
04-20-2011, 06:41 PM
It's not the general idea of relativity that I don't get, it's the specific scenario above which has never been properly explained to me: how would a FTL signal reach and stop a "cause" before it happens, but after the "effect"?

Maxx
04-20-2011, 06:44 PM
It's not the general idea of relativity that I don't get, it's the specific scenario above which has never been properly explained to me: how would a FTL signal reach and stop a "cause" before it happens, but after the "effect"?

Well, it doesn't make sense which is why FTL signals don't make sense.

glutton
04-20-2011, 06:49 PM
No, what I mean is, if there were FTL signals, WHY would they be able to reach the place where something happens before it happens? Would they go back in time or something? IOW (repost), HOW would the FTL signal reach the shooter before the gun is fired? Wouldn't it just reach the shooter before the light from the gun firing reaches the observer? If the signal is 2X the speed of light and the shooter is 8 lightyears away (for example), wouldn't 4 or more years still have passed since the firing of the gun by the time the FTL signal reaches that location? Or is there some special property of light that I'm missing?

Sarpedon
04-20-2011, 06:50 PM
I'm not so sure that Joe wouldn't just see Dmitri's capsule distorted just enough for the light to arrive at all its surfaces at the same time because Joe sees Dmitri's capsule in terms of a Lorentz contraction.

Would a lorenz contraction distort the capsule unequally?

Sarpedon
04-20-2011, 06:51 PM
Or is there some special property of light that I'm missing?

The special quality of light is that its the fastest thing possible.

glutton
04-20-2011, 06:59 PM
As expected, NO real explanation of why something traveling FTL would be able to reach something that's already happened before it happens... sigh...

Maxx
04-20-2011, 07:00 PM
Would a lorenz contraction distort the capsule unequally?

The Lorentz contraction would influence interactions, but I guess I was wrong in that the visual effect is something else (ie not a distortion due to the Lorentz contraction).
Visually it would be actually elogated or rotated:

http://th.physik.uni-frankfurt.de/~scherer/qmd/mpegs/lampa_terrell_penrose_info.html

Maxx
04-20-2011, 07:06 PM
As expected, NO real explanation of why something traveling FTL would be able to reach something that's already happened before it happens... sigh...

The image is as follows: imagine a river with everybody drifting at the same speed (flow of time). Call the speed of the current C. Buster can only send an electrically-propelled on a wire (but less than C) cork diagonally into where Bongo will be since the current pushes the cork at C. So if Bongo can move something faster than C, he can cut the wire to Buster's cork before it reaches him by taking a more extreme diagonal back into the river's upstream past. So Bongo can avoid the event of colliding with an electified Cork (the effect) by cutting the wire upstream of Buster (an earlier time as governed by C).

PeterL
04-20-2011, 07:07 PM
Would a lorenz contraction distort the capsule unequally?

Your initial question is interesting, but the capsule would become a disk, flat and thin along the direction that it was travelling as it approached the speed of light. The Dmitry it would not change shape, but the change would only be observed to someone apart from the capsule. That is what is predicted in Special elativity. It brings up the quest ion of whether the effects of relitivistic travel are real or just optical illusions.

PeterL
04-20-2011, 07:11 PM
The image is as follows: imagine a river with everybody drifting at the same speed (flow of time). Call the speed of the current C. Buster can only send an electrically-propelled on a wire (but less than C) cork diagonally into where Bongo will be since the current pushes the cork at C. So if Bongo can move something faster than C, he can cut the wire to Buster's cork before it reaches him by taking a more extreme diagonal back into the river's upstream past. So Bongo can avoid the event of colliding with an electified Cork (the effect) by cutting the wire upstream of Buster (an earlier time as governed by C).

And, if someone got out of the river and into a car and drove upstream fast, then got into a canoe again, the person could give warning.

The idea that time travel is impossible assumes that there is nothing outside the time-space in which we operate.

Maxx
04-20-2011, 07:14 PM
Your initial question is interesting, but the capsule would become a disk, flat and thin along the direction that it was travelling as it approached the speed of light. The Dmitry it would not change shape, but the change would only be observed to someone apart from the capsule. That is what is predicted in Special elativity. It brings up the quest ion of whether the effects of relitivistic travel are real or just optical illusions.

Well, that was the picture until 1959 when Terrel and Penrose figured out that the Lorentz contraction is not actually what you see.

http://en.wikipedia.org/wiki/Terrell_rotation

Maxx
04-20-2011, 07:17 PM
And, if someone got out of the river and into a car and drove upstream fast, then got into a canoe again, the person could give warning.

The idea that time travel is impossible assumes that there is nothing outside the time-space in which we operate.

In the example, Bongo's faster than C cork travelled faster than C without leaving the river. I imagine Bongo's object would have trouble interacting with ordinary C-speed objects and this would appy even more to leaving the river and getting ahead of the current.

glutton
04-20-2011, 07:22 PM
The image is as follows: imagine a river with everybody drifting at the same speed (flow of time). Call the speed of the current C. Buster can only send an electrically-propelled on a wire (but less than C) cork diagonally into where Bongo will be since the current pushes the cork at C. So if Bongo can move something faster than C, he can cut the wire to Buster's cork before it reaches him by taking a more extreme diagonal back into the river's upstream past. So Bongo can avoid the event of colliding with an electified Cork (the effect) by cutting the wire upstream of Buster (an earlier time as governed by C).

So is the current supposed to be the speed of light, or the speed of time?? I'm not seeing the logic for the two to be equated...

PeterL
04-20-2011, 07:32 PM
In the example, Bongo's faster than C cork travelled faster than C without leaving the river. I imagine Bongo's object would have trouble interacting with ordinary C-speed objects and this would appy even more to leaving the river and getting ahead of the current.

We have to decide whether a faster than c thing can exist, and if it can whether it can interact with something that is slower than C.


Getting out of the river is cheating, according to some people, but it probably is the easy way, and it appears that is a possibility, but it depends on who one believes about which theory.

PeterL
04-20-2011, 07:36 PM
Well, that was the picture until 1959 when Terrel and Penrose figured out that the Lorentz contraction is not actually what you see.

http://en.wikipedia.org/wiki/Terrell_rotation

It depends on where the observer is in relation to the passing object, and my observer saw one thing, but he doesn't know what your observer saw.

Maxx
04-20-2011, 07:40 PM
So is the current supposed to be the speed of light, or the speed of time?? I'm not seeing the logic for the two to be equated...

C is the speed of light and therefore the speed at which things can interact. There's no speed for time just as there is no speed for left and right or up and down. Effectively though, since you can't interact with things you can't ever get to (the past) and since you can only get to things at C (things you can get to = the future), C acts to govern where you are in terms of time just as being 50 feet left of x governs you in terms of x. So C as a current works because it is the flow of local interactions.

http://en.wikipedia.org/wiki/Spacetime

Astronomer
04-20-2011, 07:46 PM
If the signal is 2X the speed of light and the shooter is 8 lightyears away (for example), wouldn't 4 years still have passed since the firing of the gun even if the signal is sent at the same time the gun is fired?
Yes, you are right. As with comedy, experiments in causality depend on the adage that 'timing is everything.' :) When dealing with tiny intervals of time, like the flight of a bullet from the muzzle of a gun to an apple, you'll need to bring your lab partners a lot closer than 8 light years.

But you make an excellent point in that not every FTL event will lead to a potential paradox in every reference frame. The reference frame you've chosen doesn't allow a paradox to occur, but that doesn't mean those reference frames don't exist.

Look at it this way: If someone were to send you an FTL signal indicating what he intends to do before you're able to see him do it, there exists an interval of time in which he can change his mind between the FTL signal and the light signal, which is an opening for a paradox to occur. When he "actually" does it is irrelevant, as difficult as that is to swallow.


I'm not so sure that Joe wouldn't just see Dmitri's capsule distorted just enough for the light to arrive at all its surfaces at the same time because Joe sees Dmitri's capsule in terms of a Lorentz contractionJoe would indeed see Dmitri's capsule contracted, but he would still see the light from the bulb hit the back of the capsule before it hits the front. Again, both realities are perfectly objective and valid, even though the events don't occur in the same order from the two vantage points. Moreover, Dmitri doesn't have to reach relativistic speeds for Joe to see this happen. It's something that can be measured (well, calculated anyway) at school-zone speeds.

glutton
04-20-2011, 08:17 PM
Look at it this way: If someone were to send you an FTL signal indicating what he intends to do before you're able to see him do it, there exists an interval of time in which he can change his mind between the FTL signal and the light signal, which is an opening for a paradox to occur. When he "actually" does it is irrelevant, as difficult as that is to swallow.

You do mean "indicating what he's done", don't you? Since I wouldn't think him changing his mind would create an actual paradox any more than me sending a text saying I'll call, and then not calling. But even then how would that be a paradox, seeing that he would already have done whatever it was after the FTL signal but before the light signal reaches you, so how would you/him be able to change it (between the FTL and the light signal)?

Sarpedon
04-20-2011, 08:27 PM
Yeah, I think there's a flaw in the example. I think the flaw in the example is admitting the possibility of the FTL in the first place.

The thing about light is that has unique properties. As soon as you allow something faster than it, you might as well be talking about people sending messages, one via pigeon, another via kestrel. One is faster than the other, but both are in the same realm. You are assuming an equivalence in the example that doesn't exist.

glutton
04-20-2011, 08:32 PM
Okay, that helps a little... since I can understand that "nothing can travel faster than light" as a rule... just not "because it would cause a time paradox" which is what doesn't make sense to me at all.

Ie. I could accept that moving faster than light is impossible, it just makes zero sense to me that if something could do it, it would cause a time paradox.

kuwisdelu
04-20-2011, 09:17 PM
I hate this style of reply because it does not nest previous replies.

Okay. As far as I remember, you question my understanding of the word dimension. I question your understanding of that word as well. The quote you said doesn't contain the word 'dimension' was the wrong thing to post.

For most of my post, I was referring to your assertion that viruses are 2D. You also seemed to be conflating the possibilities of greater dimensions than four with the possibility of parallel universes; if you understand that they're different things, I misunderstood you.

Smileycat
04-20-2011, 10:54 PM
For most of my post, I was referring to your assertion that viruses are 2D. You also seemed to be conflating the possibilities of greater dimensions than four with the possibility of parallel universes; if you understand that they're different things, I misunderstood you.

I do that to a lot of people. It must be my mind, thinking everyone knows what I mean.

About 2D viruses/bacteria. I used that as an example for their movement and tiny little world. Also, I read somewhere that someone thought that they might be looked at as if they were 2D, not that they really were. Heck! I read where this one guy thinks worms are one dimensional! Worms! Because he thinks their perception of their world is forward and back only. But that really isn't true anyway, because I've seen worms climb.

Glad we got that settled, kuwisdelu.

Smileycat
04-20-2011, 10:57 PM
As expected, NO real explanation of why something traveling FTL would be able to reach something that's already happened before it happens... sigh...

I hadn't thought of that, Glutton. Let's ask Michio Kaku!

I asked him your question at http://www.pbs.org/wgbh/nova/secretlife/scientists/michio-kaku/show/ask-michio-your-questions/

Smileycat
04-20-2011, 11:08 PM
Haven't read the Kaku post but am willing to bet £1M that it doesn't aver that viruses are 2D.

You have £1M? Holy crap! Not me!

Anyway, no it wasn't him. It was someone else. And I didn't mean to say it is fact. I wondered about it as someone who is very smart (that I used to know - since passed) said he thought that viruses and bacteria could be compared to 2nd dimensional lifeforms. Hope that's it. I will try to be very careful how I word things.

Smileycat
04-20-2011, 11:19 PM
Okay, that helps a little... since I can understand that "nothing can travel faster than light" as a rule... just not "because it would cause a time paradox" which is what doesn't make sense to me at all.

Ie. I could accept that moving faster than light is impossible, it just makes zero sense to me that if something could do it, it would cause a time paradox.


Oops. I think I didn't understand you. Here's what Michio Kaku says about traveling faster than the speed of light:
http://bigthink.com/ideas/24863.


Also, I found these articles on the subject:

Baylor scientists - bubble - http://www.spacedaily.com/reports/Traveling_Faster_Than_the_Speed_of_Light_999.html
2 German scientists - prisms - http://www.sott.net/articles/show/195421-German-scientists-We-have-broken-speed-of-light
Wiki answers - http://wiki.answers.com/Q/Can_anything_move_faster_than_the_speed_of_light
:)

Smileycat
04-20-2011, 11:20 PM
I think Kaku would say we live in an effectively 4 dimensional universe (3 space + 1 time dimension).
In the above blurb, the multiverse Kaku describes is a kind of tree of supersymmetries with many big-bang style universes bubbling from it. This would be different from the many-worlds style multiverse since the separate bubbles have separate histories.

I already posted a video earlier in this thread where he says we live in a third dimensional world.

Smileycat
04-20-2011, 11:23 PM
Here's another example: Joe is an astronaut in space. Cosmonaut Dmitry zips by in his spherical, semi-transparent space capsule, travelling at a constant speed. In the center of Dmitry's capsule there's a flashing lightbulb. From Dmitry's point of view, he is at rest, since he's not accellerating (he sees Joe zipping by). The light from the flashing lightbulb arrives simultaneously on all the walls of the capsule. From Joe's point of view, because the capsule is moving, the light from the lightbulb arrives at the back of the capsule before it reaches the front of the capsule, because in the time that it takes the light to reach the walls of the capsule, the capsule has moved.

Events that are simultaneous from one frame of reference are not necessarily simultaneous from another one. This has nothing to do with the amount of time it takes the reflected light to reach the observer. (this example is not original to me, I got it from a physics book, who's name escapes me at the moment)

I find that part very interesting. Thanks for posting it.

glutton
04-21-2011, 12:01 AM
Oops. I think I didn't understand you. Here's what Michio Kaku says about traveling faster than the speed of light:
http://bigthink.com/ideas/24863.


Also, I found these articles on the subject:

Baylor scientists - bubble - http://www.spacedaily.com/reports/Traveling_Faster_Than_the_Speed_of_Light_999.html
2 German scientists - prisms - http://www.sott.net/articles/show/195421-German-scientists-We-have-broken-speed-of-light
Wiki answers - http://wiki.answers.com/Q/Can_anything_move_faster_than_the_speed_of_light
:)

No, you understood me better before; as the question you previously posted to him was more relevant to the problem I have.

Smileycat
04-21-2011, 12:23 AM
No, you understood me better before; as the question you previously posted to him was more relevant to the problem I have.


Okay. Well, we'll see if he answers us. I gave them my email address. If he answers, I'll post it in this thread, okay?

Hallen
04-21-2011, 02:00 AM
Okay, I think I understand. Please correct me if I am wrong. You are saying there is no other possibility other than the Big Bang (that started our Universe)?

That is why I asked if it wasn't possible that the Bible got something right in that our Universe always existed (I view God as the Universe).

What do you think?

Wow, this thread is expanding faster than the universe is...

No, I'm not saying that the only possibility is the big bang. I don't think anybody can say that definitively. I suppose that it is possible that the neverending universe is what we have, but the prevailing theory at the moment is that the universe -- as we know it -- did have a "start" of some kind.

What I'm trying to point to is that the event that started our universe most likely has a profound impact on how physics work. If you create a universe in a different way than ours was created, then it would most likely have different physics than we have. Therefore, the experiment would be moot because the physics are different.

If, however, the universe has always existed and will always exist, then I don't see how that has an impact on the experiment. We are pretty confident that the section of the universe we are in started at a point and expanded out from there. If that wasn't the actual start of the universe, but just an expansion thereof, then I can't see how that changes things. The physics still hold.

Anyway, my viewpoint is a philosophical one and probably shouldn't be in this thread.


EDIT: Also, here's some pretty cool short videos on physics. There's some good stuff on general relativity.

Physics X (http://www.youtube.com/user/ThePhysicsX#p/c/02BFAF4554A77F78/55/XYSvLLdaHys)

This is a cool series of videos describing really cool physics concepts like the speed of light and some really crazy physics theories (like paradox: something that can't happen but does).

Click on the Physics X playlist and scroll to the bottom. Click to expand the list. The first couple are a bit dull, but the ones that are titled Special Relativity I, II, and III are really cool.

Smileycat
04-21-2011, 01:49 PM
Wow, this thread is expanding faster than the universe is...

No, I'm not saying that the only possibility is the big bang. I don't think anybody can say that definitively. I suppose that it is possible that the neverending universe is what we have, but the prevailing theory at the moment is that the universe -- as we know it -- did have a "start" of some kind.

What I'm trying to point to is that the event that started our universe most likely has a profound impact on how physics work. If you create a universe in a different way than ours was created, then it would most likely have different physics than we have. Therefore, the experiment would be moot because the physics are different.

If, however, the universe has always existed and will always exist, then I don't see how that has an impact on the experiment. We are pretty confident that the section of the universe we are in started at a point and expanded out from there. If that wasn't the actual start of the universe, but just an expansion thereof, then I can't see how that changes things. The physics still hold.

Anyway, my viewpoint is a philosophical one and probably shouldn't be in this thread.


EDIT: Also, here's some pretty cool short videos on physics. There's some good stuff on general relativity.

Physics X (http://www.youtube.com/user/ThePhysicsX#p/c/02BFAF4554A77F78/55/XYSvLLdaHys)

This is a cool series of videos describing really cool physics concepts like the speed of light and some really crazy physics theories (like paradox: something that can't happen but does).

Click on the Physics X playlist and scroll to the bottom. Click to expand the list. The first couple are a bit dull, but the ones that are titled Special Relativity I, II, and III are really cool.


Hi, Hallen. Thanks for getting back to me. Okay, think I understand. Because some fluid mechanic experiments on a few Space Shuttle mission show that fluid mechanic laws do not hold true just a few miles above the Earth, it made me think that physic laws also MAY NOT (not do not) hold true for other types of stars (our Sun is a G2V type star - see http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml).

As you can see in the first chart, there are other types of stars that we know about and have classified. There might be others we haven't yet classified (so far out that we haven't actually seen them yet). Anyway, on the charts listed in that link, there are also subtype charts, etc., too. What if the laws of physics that apply to our Sun and its planets do not apply to them? What if the laws of physics for, say, a type K star were so different, that a new set of laws governing the physics had to be set?

I welcome philosophical remarks/questions. I do it all the time...

Thanks for the physics link! I'll check it out a little later.

Maxx
04-21-2011, 03:38 PM
I already posted a video earlier in this thread where he says we live in a third dimensional world.

Well he's wrong. We live in a world with at least 4 dimensions: 3 space dimensions and 1 time dimension which you can see for yourself by the following simple experiment you can do at home:

put a small table on top of a larger table. Make a triangle out of clocks on the large table and put another clock on the small table. Find a position from which you can see all the clocks. That looks like 3 dimensions doesn't it? And then let the clocks run on their own for a second. as you can see the first second is different from the second second and that's a measure of the time dimension. So at least 4 dimensions as easily shown with no more equipment than two tables of different sizes and innumerable clocks.

Sarpedon
04-21-2011, 04:48 PM
But all my clocks are round! How do I make a triangle from them?

Maxx
04-21-2011, 05:01 PM
But all my clocks are round! How do I make a triangle from them?

You have quite a few options:

1) paint little red (or light green) triangles on the clocks
2) glue plastic pins to the clocks
3) use a loop of twine (no twine theory please a this point) to work out the triangle
4) stand at the other side of the room and squint
5) imagine each clock is the size of a virus

And that's just the beginning!!!!

Maxx
04-21-2011, 05:05 PM
As you can see in the first chart, there are other types of stars that we know about and have classified. There might be others we haven't yet classified (so far out that we haven't actually seen them yet). Anyway, on the charts listed in that link, there are also subtype charts, etc., too. What if the laws of physics that apply to our Sun and its planets do not apply to them? What if the laws of physics for, say, a type K star were so different, that a new set of laws governing the physics had to be set?

I welcome philosophical remarks/questions. I do it all the time...

Thanks for the physics link! I'll check it out a little later.

If the laws of physics don't apply to different types of stars, how do you know there are different types of stars?
Maybe there only appear to be different types of stars? Or maybe the laws of physics do apply and you can tell a K2 star is a K2 star.

Or to put it another way, it's only by applying the laws of physics to such things as stellar spectra that one knows there are different types of stars. That being the case, if there are observable different types of stars then the laws of physics apply where-ever those different types of stars are observed.

I strongly suspect that when "philosophy" is invoked, it should make elementry logical sense or what is the point in invoking it?

Smileycat
04-21-2011, 07:14 PM
Well he's wrong. We live in a world with at least 4 dimensions: 3 space dimensions and 1 time dimension which you can see for yourself by the following simple experiment you can do at home:

put a small table on top of a larger table. Make a triangle out of clocks on the large table and put another clock on the small table. Find a position from which you can see all the clocks. That looks like 3 dimensions doesn't it? And then let the clocks run on their own for a second. as you can see the first second is different from the second second and that's a measure of the time dimension. So at least 4 dimensions as easily shown with no more equipment than two tables of different sizes and innumerable clocks.

Hi, Maxx. Don't get me wrong. I can plainly see why you think that, but I already also posted why he may be correct. I think time affects all the dimensions we know about. I think it is a special dimension in that sense. However, I also think that we, in the third dimension also contain the 1st and 2nd dimensions, but it is a little difficult for 'anyone' existing in those 2 lower dimensions to fully realize the 3rd dimension, even though I am sure a third dimensional object touches down on them quite often.

To them, it may seem like a structure or a fleeting moment, who knows. Say a glass of sparkling water is set down on top a piece of paper (often used to illustrate the 2nd dimension). Before the glass came, the piece of paper and any of its inhabitants had an unobstructed 'view' of its 'world.' Then, all of a sudden, there is a curved plane (bottom of the glass) interrupting the landscape. When someone picks up the glass - whoosh! - it's gone. A UFO?

At any rate, I think that the real 4th dimension is more than just time passing in a linear fashion. When it invades us (which is most of the, um, time), we perceive it as steadily going forward. But, there are occasions when people and things are thrown off by time oddities as demonstrated in the anecdotal book by Jenny Randles called Time Storms: The Amazing Evidence of Time Warps, Space Rifts and Time Travel. Do you think you know what I'm talking about? Sometimes I am not sure if I explained myself correctly.

Smileycat
04-21-2011, 07:22 PM
If the laws of physics don't apply to different types of stars, how do you know there are different types of stars?
Maybe there only appear to be different types of stars? Or maybe the laws of physics do apply and you can tell a K2 star is a K2 star.

Or to put it another way, it's only by applying the laws of physics to such things as stellar spectra that one knows there are different types of stars. That being the case, if there are observable different types of stars then the laws of physics apply where-ever those different types of stars are observed.

I strongly suspect that when "philosophy" is invoked, it should make elementry logical sense or what is the point in invoking it?

They don't actually use our physics laws to classify star types. "Stars are classified by their spectra (the elements that they absorb) and their temperature. There are seven main types of stars. In order of decreasing temperature, O, B, A, F, G, K, and M" from the same link I posted earlier - http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml. They use a spectrometer for the spectra and filters for the temperature (to determine color, which indicates temperature range). Granted, they use instruments made on Earth, but this would all be relative to us anyway.

Astronomer
04-21-2011, 07:29 PM
Glutton, your question is difficult to answer, and I'm sorry my examples haven't risen to the occasion.

Here's a paragraph from Wikipedia that probably won't help, since it simply states the problem with no explanation:

Some observers with sub-light relative motion will disagree about which occurs first of any two events that are separated by a space-like interval. In other words, any travel that is faster-than-light will be seen as traveling backwards in time in some other, equally valid, frames of reference, or need to assume the speculative hypothesis of possible Lorentz violations at a presently unobserved scale (for instance the Planck scale). Therefore any theory which permits "true" FTL also has to cope with time travel and all its associated paradoxes, or else to assume the Lorentz invariance to be a symmetry of thermodynamical statistical nature (hence a symmetry broken at some presently unobserved scale).The article is here:
http://en.wikipedia.org/wiki/Faster-than-light

This is not the same thing as saying that FTL is the same thing as time travel, though it would certainly simplify things if that were the case.

Smileycat
04-21-2011, 07:31 PM
Glutton, your question is difficult to answer, and I'm sorry my examples haven't risen to the occasion.

Here's a paragraph from Wikipedia that probably won't help, since it simply states the problem with no explanation:
The article is here:
http://en.wikipedia.org/wiki/Faster-than-light

This is not the same thing as saying that FTL is the same thing as time travel, though it would certainly simplify things if that were the case.

A valiant effort, Astronomer! Are you one in real life?

Astronomer
04-21-2011, 07:51 PM
A valiant effort, Astronomer! Are you one in real life?Alas, I'm only an amateur astronomer, though in my day job, I am a staff scientist (applied, not academic). I love astronomy enough, though, that I've started a blog championing its virtues to the masses, to those with little opportunity to look up, but who can still enjoy its wonders.

Maxx
04-21-2011, 07:53 PM
Do you think you know what I'm talking about? Sometimes I am not sure if I explained myself correctly.

I just pointed out that we live in a world that seems to have at least 4 dimensions.

Maxx
04-21-2011, 07:56 PM
They don't actually use our physics laws to classify star types. "Stars are classified by their spectra (the elements that they absorb) and their temperature. There are seven main types of stars. In order of decreasing temperature, O, B, A, F, G, K, and M" from the same link I posted earlier - http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml. They use a spectrometer for the spectra and filters for the temperature (to determine color, which indicates temperature range). Granted, they use instruments made on Earth, but this would all be relative to us anyway.

Without physical laws the concepts of the spectra and temperature of a distant object (assumed to be a star and the notion of star is a highly developed construct requiring all the laws of physics) don't mean anything at all. "Relative to us" includes the ideas of "meaningful and logical to us" not just whatever happens to be next to us.

kuwisdelu
04-21-2011, 10:47 PM
Hi, Maxx. Don't get me wrong. I can plainly see why you think that, but I already also posted why he may be correct. I think time affects all the dimensions we know about. I think it is a special dimension in that sense.

It's just another coordinate orthogonal to all previously defined dimensions (i.e., our three spatial dimensions). Our relationship to it is special in the sense that we can't move along it freely like we can the other dimensions.


However, I also think that we, in the third dimension also contain the 1st and 2nd dimensions

Dimensions cannot "contain" any other dimensions. (The rest of your example makes sense, though.)


They don't actually use our physics laws to classify star types. "Stars are classified by their spectra (the elements that they absorb) and their temperature. There are seven main types of stars. In order of decreasing temperature, O, B, A, F, G, K, and M" from the same link I posted earlier - http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml. They use a spectrometer for the spectra and filters for the temperature (to determine color, which indicates temperature range). Granted, they use instruments made on Earth, but this would all be relative to us anyway.

Except as Maxx pointed out, 1) how we measure those spectra relies on our knowledge of physics and chemistry and 2) there's no reason to believe the laws of physics would be different for them.

Speaking of which, sorry if I missed it earlier, but can you tell or link me to a description of your fluid mechanics example? Preferably something with equations in it.

And furthermore, what exactly do you mean by "don't apply to other types of stars"? Do you mean, for example, that a star may be made of a kind of matter for which the gravitational constant is different, or has negative mass, or something like that? If you're proposing the existence of exotic matter with different physical characteristics, then that makes a lot more sense than what it sounds like you're saying.

Smileycat
04-22-2011, 02:31 AM
Alas, I'm only an amateur astronomer, though in my day job, I am a staff scientist (applied, not academic). I love astronomy enough, though, that I've started a blog championing its virtues to the masses, to those with little opportunity to look up, but who can still enjoy its wonders.

Interesting. I, also, am an amateur astronomer. But I don't get out as much as I like anymore. Oh, well.

And, you are also a writer?

Smileycat
04-22-2011, 02:33 AM
I just pointed out that we live in a world that seems to have at least 4 dimensions.

Your answer indicates that you do not understand what I mean. That's okay. I don't know how else to explain it right now...

Torgo
04-22-2011, 02:40 AM
Your answer indicates that you do not understand what I mean. That's okay. I don't know how else to explain it right now...

Have you read 'Flatland' by Edwin Abbott? (Or 'The Planiverse' by AK Dewdney?) They both involve situations like the ones you've described.

Astronomer
04-22-2011, 02:45 AM
And, you are also a writer?Self-delusion notwithstanding, yes. ;)

Smileycat
04-22-2011, 02:54 AM
Without physical laws the concepts of the spectra and temperature of a distant object (assumed to be a star and the notion of star is a highly developed construct requiring all the laws of physics) don't mean anything at all. "Relative to us" includes the ideas of "meaningful and logical to us" not just whatever happens to be next to us.

The Law of Physics is not quite the same as physical law. Go here http://en.wikipedia.org/wiki/Physics for a basic description of physics. Basically, "Physics (from Ancient Greek (http://www.absolutewrite.com/wiki/Ancient_Greek): φύσις physis (http://www.absolutewrite.com/wiki/Physis) "nature") is a natural science (http://www.absolutewrite.com/wiki/Natural_science) that involves the study of matter (http://www.absolutewrite.com/wiki/Matter) and its motion (http://www.absolutewrite.com/wiki/Motion_(physics)) through spacetime (http://www.absolutewrite.com/wiki/Spacetime), as well as all related concepts, including energy (http://www.absolutewrite.com/wiki/Energy) and force (http://www.absolutewrite.com/wiki/Force). More broadly, it is the general analysis of nature (http://www.absolutewrite.com/wiki/Nature), conducted in order to understand how the universe (http://www.absolutewrite.com/wiki/Universe) behaves."

Here's what Wiki says about Physical Law: "A physical law or scientific law is a scientific (http://www.absolutewrite.com/wiki/Scientific) generalization based on empirical (http://www.absolutewrite.com/wiki/Empiricism) observations (http://www.absolutewrite.com/wiki/Observation) of physical behaviour (i.e. the law of nature). Laws of nature are observable. Scientific laws are empirical, describing observable patterns. Empirical laws are typically conclusions based on repeated scientific (http://www.absolutewrite.com/wiki/Science) experiments (http://www.absolutewrite.com/wiki/Experiment) and simple observations, over many years, and which have become accepted universally within the scientific community (http://www.absolutewrite.com/wiki/Scientific_community). The production of a summary description of our environment in the form of such laws is a fundamental aim of science. These terms are not used the same way by all authors. Some philosophers e.g. Norman Swartz (http://www.absolutewrite.com/wiki/Norman_Swartz) use "physical law" to mean what others mean by "natural law"/"law of nature".

"Laws of nature are distinct from religious (http://www.absolutewrite.com/wiki/Religious_law) and civil (http://www.absolutewrite.com/wiki/Law) law, and should not be confused with the concept of natural law (http://www.absolutewrite.com/wiki/Natural_law). Nor should 'physical law' be confused with 'law of physics (http://www.absolutewrite.com/wiki/Physics)' - the term 'physical law' usually covers laws in other sciences (e.g. biology) as well," from http://en.wikipedia.org/wiki/Law_of_physics (large font and bolding is mine).

As you can read, the Law of Physics are different. (See Physics above.)

Smileycat
04-22-2011, 02:57 AM
Self-delusion notwithstanding, yes. ;)

Don't put yourself down just yet. I didn't ask if you were a good writer. :tongue

Smileycat
04-22-2011, 03:21 AM
It's just another coordinate orthogonal to all previously defined dimensions (i.e., our three spatial dimensions). Our relationship to it is special in the sense that we can't move along it freely like we can the other dimensions.

Dimensions cannot "contain" any other dimensions. (The rest of your example makes sense, though.)

Except as Maxx pointed out, 1) how we measure those spectra relies on our knowledge of physics and chemistry and 2) there's no reason to believe the laws of physics would be different for them.

Speaking of which, sorry if I missed it earlier, but can you tell or link me to a description of your fluid mechanics example? Preferably something with equations in it.

And furthermore, what exactly do you mean by "don't apply to other types of stars"? Do you mean, for example, that a star may be made of a kind of matter for which the gravitational constant is different, or has negative mass, or something like that? If you're proposing the existence of exotic matter with different physical characteristics, then that makes a lot more sense than what it sounds like you're saying.

It (4th dimension) is unobtainable by us third dimensional beings, make no mistake about that. When I said contain, I perhaps should have used the word 'interacts' with the 4th dimension. But, make no mistake about it, we are not living in the fourth dimension. I used an example of a third dimensional object touching down on the second and perhaps first dimensions, looking like a UFO to them. Perhaps that also happens to us and other higher dimensional objects. The presumed fourth dimension of 'time' is such that it seems to affect all of us, except when it doesn't. I think that is because we don't actually exist in the fourth dimension. That's all I have to say about that. I don't know how else to explain my opinion on it.

Please read my reply to Maxx on the difference between Physical Law and Law of Physics.

I already stated that you can go to NASA's webpage on shuttle missions and spend hours looking for all the fluid experiments they did in space. One (or two) of them turned our on Earth' experiments upside down. I have no link to give you except for the main one - http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/list_main.html. Happy hunting!

I looked for this quote - "don't apply to other types of stars" that you attributed to me, but didn't see it. What's the number of that post?

Smileycat
04-22-2011, 03:22 AM
Have you read 'Flatland' by Edwin Abbott? (Or 'The Planiverse' by AK Dewdney?) They both involve situations like the ones you've described.

No, I haven't. Haven't read any sci-fi for many years now. Are they good? I think the last sci-fi genre book I read was by Larry Niven.

kuwisdelu
04-22-2011, 04:27 AM
And, you are also a writer?

Well, we're on a writing forum and his responses are far too sharp for him to be spam, I think. ;)

Torgo
04-22-2011, 04:34 AM
No, I haven't. Haven't read any sci-fi for many years now. Are they good? I think the last sci-fi genre book I read was by Larry Niven.

They're not really SF. Flatland is an 1884 satirical novel - thanks, Wikipedia - actually, go read the Wiki page (http://en.wikipedia.org/wiki/Flatland). You can read it here (http://xahlee.org/flatland/index.html), or there are versions on Project Gutenberg in various flavours of ebook.

The Planiverse (http://en.wikipedia.org/wiki/The_Planiverse) is a rather excellent and even moving flight of fancy in which a college professor and his students accidentally contact a real 2D universe, via their computer simulation of same. Where Flatland is satirical, The Planiverse works out its world quite rigorously, and it's full of marvellous illustrations of how things like hot air balloons might work in 2D. (in 2 dimensions, a rope can become a balloon.)

The reason I mention them is that in both novels there are, to a greater or lesser extent, intrusions into the flat world from the 3D universe (like ours. I should probably say, when I say 2D and 3D I'm not counting time, just the obvious spatial dimensions.) So a sphere moving through the plane of a 2D universe manifests as a point growing to a circle - the sphere's circumference - and then shrinking back to a point again. The denizens of 2D world only see a slice of the 3D sphere as it transects their reality.

So people have written plenty of stories in which entities from universes with more spatial dimensions manifest in our universe - that UFO effect that you mention. But so far as we know, they're just stories. Also, the place these UFOs would be coming from would not be 'the fourth dimension' or even 'another dimension' - they'd be from another universe entirely.

kuwisdelu
04-22-2011, 04:37 AM
It (4th dimension) is unobtainable by us third dimensional beings, make no mistake about that. When I said contain, I perhaps should have used the word 'interacts' with the 4th dimension. But, make no mistake about it, we are not living in the fourth dimension.

I can describe myself, you, or anything else in this world in a unique time and place with a 4-vector. There's nothing "unobtainable" about time. We travel through it all the time. I'm traveling through it right now and so are you. Just because we can't control how we move along it the same way we can control how we move along the other three dimensions doesn't mean we don't have any existence along it. It's a limited one, but it's certainly there. If we only existed at one point in time, we'd pop out of existence in an instant.


Please read my reply to Maxx on the difference between Physical Law and Law of Physics.

The difference doesn't really affect anything I said before.


I already stated that you can go to NASA's webpage on shuttle missions and spend hours looking for all the fluid experiments they did in space. One (or two) of them turned our on Earth' experiments upside down. I have no link to give you except for the main one - http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/list_main.html. Happy hunting!

Not now, thanks. I have dozens of simulations to run by tomorrow and way too much programming to do for a project over the weekend.


I looked for this quote - "don't apply to other types of stars" that you attributed to me, but didn't see it. What's the number of that post?

Here, (http://www.absolutewrite.com/forums/showpost.php?p=6060526&postcount=162) where you conjectured that our physics may not "apply" to other stars. Can you be more specific??

ColoradoMom
04-22-2011, 04:48 AM
They're not really SF. Flatland is an 1884 satirical novel - thanks, Wikipedia - actually, go read the Wiki page (http://en.wikipedia.org/wiki/Flatland). You can read it here (http://xahlee.org/flatland/index.html), or there are versions on Project Gutenberg in various flavours of ebook.

The Planiverse (http://en.wikipedia.org/wiki/The_Planiverse) is a rather excellent and even moving flight of fancy in which a college professor and his students accidentally contact a real 2D universe, via their computer simulation of same. Where Flatland is satirical, The Planiverse works out its world quite rigorously, and it's full of marvellous illustrations of how things like hot air balloons might work in 2D. (in 2 dimensions, a rope can become a balloon.)



Don't forget this classic (well, recent classic) It's mind blowing!

http://www.youtube.com/watch?v=JkxieS-6WuA (Part One)

The Whole she-bang
http://www.tenthdimension.com/

benbradley
04-22-2011, 06:34 AM
They don't actually use our physics laws to classify star types. "Stars are classified by their spectra (the elements that they absorb) and their temperature. There are seven main types of stars. In order of decreasing temperature, O, B, A, F, G, K, and M" from the same link I posted earlier - http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml. They use a spectrometer for the spectra and filters for the temperature (to determine color, which indicates temperature range). Granted, they use instruments made on Earth, but this would all be relative to us anyway.

The Law of Physics is not quite the same as physical law.
This seems a wee bit pedantic.

I see Maxx's point - star temperature is discerned from star color through the study of black-body radiation, which is part of physics. This is the same radiation given off by an electric heating element or electric stove "burner," the dull orange-red when it gets up to temperature, and the light from an old-fashioned incandescent light bulb. It is because of the study of black-body radiation (how the energy radiated from an object varies with temperature) that one is able to tell the temperature of a distant object from the spectrum of radiation it emits.

Smileycat
04-22-2011, 09:52 AM
Well, we're on a writing forum and his responses are far too sharp for him to be spam, I think. ;)

Are you buddies? Is that why you're speaking for him? He already answered me, in case you didn't notice. I am just trying to get to know him (on my own). Just like I tried to understand you.

Smileycat
04-22-2011, 09:54 AM
They're not really SF. Flatland is an 1884 satirical novel - thanks, Wikipedia - actually, go read the Wiki page (http://en.wikipedia.org/wiki/Flatland). You can read it here (http://xahlee.org/flatland/index.html), or there are versions on Project Gutenberg in various flavours of ebook.

The Planiverse (http://en.wikipedia.org/wiki/The_Planiverse) is a rather excellent and even moving flight of fancy in which a college professor and his students accidentally contact a real 2D universe, via their computer simulation of same. Where Flatland is satirical, The Planiverse works out its world quite rigorously, and it's full of marvellous illustrations of how things like hot air balloons might work in 2D. (in 2 dimensions, a rope can become a balloon.)

The reason I mention them is that in both novels there are, to a greater or lesser extent, intrusions into the flat world from the 3D universe (like ours. I should probably say, when I say 2D and 3D I'm not counting time, just the obvious spatial dimensions.) So a sphere moving through the plane of a 2D universe manifests as a point growing to a circle - the sphere's circumference - and then shrinking back to a point again. The denizens of 2D world only see a slice of the 3D sphere as it transects their reality.

So people have written plenty of stories in which entities from universes with more spatial dimensions manifest in our universe - that UFO effect that you mention. But so far as we know, they're just stories. Also, the place these UFOs would be coming from would not be 'the fourth dimension' or even 'another dimension' - they'd be from another universe entirely.

Ah. The idea that we touch other dimensions doesn't originate with me. I got it from a very smart man who has passed on.

kuwisdelu
04-22-2011, 10:14 AM
Are you buddies? Is that why you're speaking for him? He already answered me, in case you didn't notice. I am just trying to get to know him (on my own). Just like I tried to understand you.

I was just attempting to inject some humor. :)

Smileycat
04-22-2011, 10:19 AM
I can describe myself, you, or anything else in this world in a unique time and place with a 4-vector. There's nothing "unobtainable" about time. We travel through it all the time. I'm traveling through it right now and so are you. Just because we can't control how we move along it the same way we can control how we move along the other three dimensions doesn't mean we don't have any existence along it. It's a limited one, but it's certainly there. If we only existed at one point in time, we'd pop out of existence in an instant.
I can see you are not getting what I mean. Let me try one last time (then I am giving up on trying to explain myself). Since we are third dimensional, and just touch upon what is said to be (but not proved to be) the fourth dimension, we cannot know what the fourth dimension is really like. Notice that I never said TIME was indeed the fourth dimension. Others have said that and are even adamant that time IS the fourth dimension. I am not so sure. But, whatever. As third dimensional beings (and that is all we are) we cannot know what being fourth dimensional is truly like. When we touch a lower dimension, we may appear as apparitions or a fleeting figure or disappearing UFO of some kind.



The difference doesn't really affect anything I said before.
But it DOES make a difference! Further, I was addressing Maxx, not you!



Not now, thanks. I have dozens of simulations to run by tomorrow and way too much programming to do for a project over the weekend.
That has nothing to do with me.



Here, (http://www.absolutewrite.com/forums/showpost.php?p=6060526&postcount=162) where you conjectured that our physics may not "apply" to other stars. Can you be more specific??
In post # 162, what you said I said to Hallen isn't quite what I posted! This is what I said, "Hi, Hallen. Thanks for getting back to me. Okay, think I understand. Because some fluid mechanic experiments on a few Space Shuttle mission show that fluid mechanic laws do not hold true just a few miles above the Earth, it made me think that physic laws also MAY NOT (not do not) hold true for other types of stars (our Sun is a G2V type star - see http://www.enchantedlearning.com/sub...tartypes.shtml (http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml)).

"As you can see in the first chart, there are other types of stars that we know about and have classified. There might be others we haven't yet classified (so far out that we haven't actually seen them yet). Anyway, on the charts listed in that link, there are also subtype charts, etc., too. What if the laws of physics that apply to our Sun and its planets do not apply to them? What if the laws of physics for, say, a type K star were so different, that a new set of laws governing the physics had to be set?"

I asked WHAT IF the laws of physics that apply to our Sun, etc. do not apply to other classifications of stars? Our Sun is a G2V type star. I then asked what if the laws of physics do not apply to these other classifications, for instance a class K star? What if the conditions surrounding this type of star (or others) was so different that the law of physics as we know them wouldn't apply to these stars? Would a new set of laws need to be created? Suppose gravity, or other factors, are very different (there have been gravity anomalies, etc.) there than they are here? Might it not necessitate a new set of laws? Is that a better explanation?

Smileycat
04-22-2011, 10:26 AM
This seems a wee bit pedantic.

I see Maxx's point - star temperature is discerned from star color through the study of black-body radiation, which is part of physics. This is the same radiation given off by an electric heating element or electric stove "burner," the dull orange-red when it gets up to temperature, and the light from an old-fashioned incandescent light bulb. It is because of the study of black-body radiation (how the energy radiated from an object varies with temperature) that one is able to tell the temperature of a distant object from the spectrum of radiation it emits.

I quoted Wiki.

Smileycat
04-22-2011, 10:27 AM
I was just attempting to inject some humor. :)

Keep this up and I WILL adopt you. :tongue

kuwisdelu
04-22-2011, 10:46 AM
Let me try one last time (then I am giving up on trying to explain myself). Since we are third dimensional, and just touch upon what is said to be (but not proved to be) the fourth dimension, we cannot know what the fourth dimension is really like.

Unfortunately, your explanations are still suggesting to me that you don't really understand what a dimension is.

You've used it before, so I'll just quote Wikepedia: "In physics and mathematics, the dimension of a space or object is informally defined as the minimum number of coordinates needed to specify each point within it."

Dimensions are nothing more than a coordinate system. To physicists, time is a coordinate. We move along it, but not freely. That's all. It's really not any more complicated or mysterious than that. It's that simple and straightforward.

Furthermore, to uniquely specify any object or event in the observable universe, I generally need four coordinates: three spatial and one temporal.


Notice that I never said TIME was indeed the fourth dimension. Others have said that and are even adamant that time IS the fourth dimension.

Well, you're right in one sense. Which dimension is which as far as numbering goes is completely arbitrary. We could just as easily rename time the first dimension and the next three dimensions the spatial dimensions if we wanted.


But it DOES make a difference!

In the case we're talking about, physical laws agree very well with the laws of physics. You're splitting hairs.


Further, I was addressing Maxx, not you!

But you told me to read your reply to Maxx. ?


I asked WHAT IF the laws of physics that apply to our Sun, etc. do not apply to other classification of stars? Our Sun is a G2V type star. I then asked what if the laws of physics do not apply to these other classifications, for instance a class K star? What if the conditions surrounding this type of star (or others) was so different that the law of physics as we know them wouldn't apply to them. Would a new set of laws need to be created? Suppose gravity, or other factors, are very different (there have been gravity anomalies, etc.) there than they are here? Might it not necessitate a new set of laws? Is that a better explanation?

This is what I was asking you to elaborate on. There's neither reason nor any experimental evidence to believe that the laws of physics themselves vary based on your reference frame; rather, any such variability is more likely the result of latent variables in the model.

What kind of "gravity anomalies" do you mean? Based on our observations of the universe, we have very strong evidence that gravity by-and-large behaves exactly the same in all parts of the observable universe. Where our theories break down are instead in limiting cases, particularly — for gravity, i.e., general relativity — at the quantum scale. However, stars aren't quantum in nature.

I asked if you meant exotic matter. If I can frame your question in that manner, then it makes more sense to me, because physicists are indeed speculating and looking for exotic matter, such as dark matter. There are various proposed extensions to the standard model to account for this.

It's very rare to need new laws anymore. Rather, it's more common that the old model becomes a limiting case of a more general model, or is extended into a more general framework to account for the new data.

kuwisdelu
04-22-2011, 12:14 PM
I should note that none of this accounts for the possibility of magic.

Smileycat
04-22-2011, 12:30 PM
Unfortunately, your explanations are still suggesting to me that you don't really understand what a dimension is.

You've used it before, so I'll just quote Wikepedia: "In physics and mathematics, the dimension of a space or object is informally defined as the minimum number of coordinates needed to specify each point within it."

Dimensions are nothing more than a coordinate system. To physicists, time is a coordinate. We move along it, but not freely. That's all. It's really not any more complicated or mysterious than that. It's that simple and straightforward.

Furthermore, to uniquely specify any object or event in the observable universe, I generally need four coordinates: three spatial and one temporal.



Well, you're right in one sense. Which dimension is which as far as numbering goes is completely arbitrary. We could just as easily rename time the first dimension and the next three dimensions the spatial dimensions if we wanted.



In the case we're talking about, physical laws agree very well with the laws of physics. You're splitting hairs.



But you told me to read your reply to Maxx. ?



This is what I was asking you to elaborate on. There's neither reason nor any experimental evidence to believe that the laws of physics themselves vary based on your reference frame; rather, any such variability is more likely the result of latent variables in the model.

What kind of "gravity anomalies" do you mean? Based on our observations of the universe, we have very strong evidence that gravity by-and-large behaves exactly the same in all parts of the observable universe. Where our theories break down are instead in limiting cases, particularly — for gravity, i.e., general relativity — at the quantum scale. However, stars aren't quantum in nature.

I asked if you meant exotic matter. If I can frame your question in that manner, then it makes more sense to me, because physicists are indeed speculating and looking for exotic matter, such as dark matter. There are various proposed extensions to the standard model to account for this.

It's very rare to need new laws anymore. Rather, it's more common that the old model becomes a limiting case of a more general model, or is extended into a more general framework to account for the new data.

No use rehashing the same things over and over and over and over again. I'm done discussing this with you. Further, I dislike being insulted. I've already posted what 1st, 2nd and 3rd dimensions are, with reputable sites as back-up. You don't like it? Take it up with them, not me, okay?

P.S. No cookies for you today. (But, maybe tomorrow.)

Maxx
04-22-2011, 03:56 PM
The Law of Physics is not quite the same as physical law.


When somebody interprets a spectrum (and you can get spectra off of anything that puts out enough photons), they use a lot of rules and some of these are pretty basic physical laws related to constants and parameters that are observed in all kinds of things. The fact that the interpreter of a a spectrum uses the same rules for interpreting a spectrum from something with in a stone's throw of him as he uses for something many light-years away seems to suggest that most "physical laws" or rules for interpreting spectra and all the laws (reducible often to constants and equations and parameters) associated with spectra are working over vast distances constantly all the time and probably have been for at least the last 13 billion years (ie since the Big Bang).

Smileycat
04-22-2011, 11:00 PM
When somebody interprets a spectrum (and you can get spectra off of anything that puts out enough photons), they use a lot of rules and some of these are pretty basic physical laws related to constants and parameters that are observed in all kinds of things. The fact that the interpreter of a a spectrum uses the same rules for interpreting a spectrum from something with in a stone's throw of him as he uses for something many light-years away seems to suggest that most "physical laws" or rules for interpreting spectra and all the laws (reducible often to constants and equations and parameters) associated with spectra are working over vast distances constantly all the time and probably have been for at least the last 13 billion years (ie since the Big Bang).

I thought my earlier post made it quite clear that law of physics and physical laws are two different things. If you (and others) don't agree with that, go ahead and believe whatever it is you believe. But, because no matter what I say it doesn't seem to register with you, so why should I continue talking about it with you? I say let it drop. I quoted reputable sources to show you my side (and that contradicts you side). Understand my POV?

THE END

Understand that?

:Hug2:

Pthom
04-23-2011, 01:08 AM
And now that the request in the original post has been satisfied (it was for opinions, and there are now some 8 pages of opinion and much conjecture --and a little speculation), there is no reason to leave it open.

Remember, folks: this thread is for asking, answering and discussing scientific facts. Period.

Next topic.