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thisiskortny5
05-08-2016, 06:11 PM
I'm needing to speak with someone who knows anything about Einteins theory of relativity and time dilation!! If anyone can help please let me know :) (this is very general please read the rest of the comments for more information thanks!)

King Neptune
05-08-2016, 07:14 PM
General or Specific Relativity? Are you just interested in time dilation? If so, then working with the Lorenz Transformation will give you all of the relevant information.

jimmymc
05-08-2016, 07:16 PM
:Shrug:https://en.wikipedia.org/wiki/Albert_Einstein

neandermagnon
05-08-2016, 07:37 PM
For a beginner level explanation, there's the kids book "The time and space of Uncle Albert" - I can't remember the writer's name, unfortunately. It may be aimed at kids but the science in it is hard to get your head around so it's suitable reading for adults who are interested in learning about relativity. The first book focuses on special relativity but I think there's a sequel that goes into general relativity.

For something more advanced, I'd recommend "black holes, wormholes and time machines" by Jim Al Khalili (it's non-fiction, but very accessible and well-written).

Also, if you explain in more detail what you want to know, if I can answer it I will. I'm rather more into biology than physics but I've read up on the theories, albeit without the maths.

Dennis E. Taylor
05-08-2016, 07:40 PM
Yeah, you'll need to ask specific questions. It's a pretty broad topic.

thisiskortny5
05-08-2016, 07:49 PM
What I need to know is if my idea for a story makes sense at all. Would anyone be willing to speak with me privately and tell me if its even possible? Don't want to waste my time, and I want it to be believable.

- - - Updated - - -

I'm interested in time dilation in particular but as you can see I'm pretty clueless.

Telergic
05-08-2016, 08:34 PM
Really you should do some basic research first. Wikipedia should satisfy all your needs. But there is plenty of fiction out there too. For a classic, you could start with Poul Anderson's Tau Zero which should explain dilation along the way.

Filigree
05-08-2016, 09:36 PM
This search string may help.

https://www.google.com/search?q=relativity+for+dummies&oq=relativity+for&aqs=chrome.0.0j69i57j0l2j69i60.9297j0j4&sourceid=chrome-mobile&ie=UTF-8

Here's a decent search string for how to use search engines more efficiently. I have to refer back to these tips often.

https://www.google.com/search?q=how+to+use+search+engines&oq=how+tobuse+search&aqs=chrome.2.69i57j0l3.9838j0j4&sourceid=chrome-mobile&ie=UTF-8#q=how+to+use+search+engines+efficiently

One of the cool things about writing SFF is all the great nonfiction stuff we can sneak in while justifying our 'handwavium'. Unfortunately, that often means Research. Like basic self-editing, initial research is something writers need to be prepared to do themselves. Then hunt up more expert clarification once we get the basics.

King Neptune
05-08-2016, 10:11 PM
Telergic has a great suggestion. Tau Zero explains time dilation very clearly and in excruciating detail, and it's a good read.

If you are comfortable with algebra, then https://en.wikipedia.org/wiki/Lorentz_transformation should help. If you are not especially comfortable with algebra, then http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/tdil.html may do the trick; this is an online calculator, but it will require that you learn what the formula means. You might also want to read about Hendrik Lorentz https://en.wikipedia.org/wiki/Hendrik_Lorentz who was one of the devisors of the transformations about twenty years before Einstein put them into Special Relativity.

jjdebenedictis
05-08-2016, 11:05 PM
My spouse is a bonifide professorial-dude of gravity and relativity, so I could probably get you answers. I could maybe answer them myself, too; I've got a master's in physics, although I studied condensed matter.

If you're shy, you can ask a moderator to move this thread into the Brainstorming Sandbox (http://absolutewrite.com/forums/forumdisplay.php?180-Brainstorming-Sandbox)subforum. It's password-protected (password: vista) and the perfect place to bounce ideas around to see whether they work.

blacbird
05-08-2016, 11:09 PM
Simply phrased, "Einstein's Theory of Relativity" is that everything is, kind of.

caw

Dennis E. Taylor
05-08-2016, 11:59 PM
although I studied condensed matter.


I use condensed milk. Does that count? :tongue

Seriously, OP, if you really don't want to discuss it publicly (at least initially), you can PM me. I'm currently engaged in writing a multigenerational SF space opera where Einstein figures prominently.

But as a general rule, it's preferable to have discussions in public threads so that other people can learn from them as well.

thisiskortny5
05-09-2016, 01:18 AM
Okay well my idea is... Main character is taken from earth to live on a fictional planet(call it planet A). The trip is supposed to be less than a year but because of a black hole their ship is pulled into the Gravity of another planet(planet B). So in relation to earth and planet A, nine years passes. But...because of the gravity of planet B, only, i don't know, a year or so passes.
So when they finally do return to planet A, the natives to the planet that were aboard this ship are still close to the same age as when they left, but the others are nine years older. Make sense??? Please let me know if I need to elaborate more but it's like an interstellar (Mathew mconaughey movie) type thing when he visits millers planet and that gargantuan black whole effects the gravity and everyone on earth was older but he was almost the same.

King Neptune
05-09-2016, 02:49 AM
Okay well my idea is... Main character is taken from earth to live on a fictional planet(call it planet A). The trip is supposed to be less than a year but because of a black hole their ship is pulled into the Gravity of another planet(planet B). So in relation to earth and planet A, nine years passes. But...because of the gravity of planet B, only, i don't know, a year or so passes.
So when they finally do return to planet A, the natives to the planet that were aboard this ship are still close to the same age as when they left, but the others are nine years older. Make sense??? Please let me know if I need to elaborate more but it's like an interstellar (Mathew mconaughey movie) type thing when he visits millers planet and that gargantuan black whole effects the gravity and everyone on earth was older but he was almost the same.

So the black hole forced the ship to change direction and slow down. The slowing reduced the time dilation, so that the spaceship would take longer to get there. Yes, that makes sense, and it is possible to determine how long it would take in shipboard time and planetary time, but there are many possibilities as to the exact time. How fast was the ship supposed to go? If the time dilation is 1/9, then it was going mighty fast.

Dennis E. Taylor
05-09-2016, 02:59 AM
Okay well my idea is... Main character is taken from earth to live on a fictional planet(call it planet A). The trip is supposed to be less than a year but because of a black hole their ship is pulled into the Gravity of another planet(planet B). So in relation to earth and planet A, nine years passes. But...because of the gravity of planet B, only, i don't know, a year or so passes.
So when they finally do return to planet A, the natives to the planet that were aboard this ship are still close to the same age as when they left, but the others are nine years older. Make sense??? Please let me know if I need to elaborate more but it's like an interstellar (Mathew mconaughey movie) type thing when he visits millers planet and that gargantuan black whole effects the gravity and everyone on earth was older but he was almost the same.

First uncertainty is when you say "time passes", I'm not sure whether you mean stay-at-home time or ship's time.

"The trip is supposed to be less than a year". Ship's time? It would have to be, since any interstellar trip will take minimum 4 years.
"Nine years passes". Ok, that's stay-at-home time.
"Only one year passes". That's reasonable, except it wouldn't have anything to do with the black hole or the gravity of planet B. It would be because of the speed they were travelling for most of the voyage.

As for Interstellar, the pseudo-science in that movie made me cringe. Don't base anything on that movie.

The basic point here is that time slows down as you travel closer to the speed of light. So for a nine-light-year trip, maybe nine and a half years will pass on Earth, but maybe only a couple on the ship. How much exactly depends on how hard you accelerate and decelerate.

Nothing wrong with using a black hole to throw the ship off course, but that's all you'd use it for.

I can give you specific calculations if you can give me specific distances and such.

jjdebenedictis
05-09-2016, 03:03 AM
If the gravity of Planet B is strong enough to cause noticeable time dilation effects, then it would crush human life. However, you can have time dilation effects just from going fast enough.

The gravity of the black hole (a planet probably wouldn't be enough) could speed them up so fast their relative aging slows down the way you want it to. However, the nine years' worth of earth-time has to pass while they're traveling at those very fast (close to the speed of light) speeds, which means they're covering a lot of distance too.

So you could have the black hole slingshot them deep into space, and then they have to figure out that it's happened, arrange to turn around (being slingshotted back the way they came by another black hole would be the best choice), and aim correctly to wind up back home rather than lost deep in another piece of space.

thisiskortny5
05-09-2016, 03:58 AM
so it would have to be caused by velocity not gravity? or maybe both? i understand for the results i want, (1 year on ship for 9 on earth) would make it hard to explain. the reason i need it to be such a long time is because six years after the ship returns to Planet A, the protagonist's sister is taken from earth just like she was, but they don't have the "issues" with the blackhole, the trip from earth to planet A goes as it should. so . .. where protagonist should be 7 years old than her sister she is the same age. god does this even make any sense? also i don't want it to have to take a minimum of 4 years like ANGRY GUY said. haha. that sort of throws the entire thing off.. hmmmmm... damn.

jjdebenedictis
05-09-2016, 04:59 AM
Yeah, the closest star to Earth is about 4 light-years away, and nothing travels faster than light, so that's your minimum.

IF you're using Earth. If your protagonists are living on New Earth, however, in the heart of the galaxy where the stars are much closer together, then you could have stars only one lightyear away or less from New Earth, and it would be much more plausible you'd find a stray black hole wandering through the area.

King Neptune
05-09-2016, 05:11 AM
so it would have to be caused by velocity not gravity? or maybe both? i understand for the results i want, (1 year on ship for 9 on earth) would make it hard to explain. the reason i need it to be such a long time is because six years after the ship returns to Planet A, the protagonist's sister is taken from earth just like she was, but they don't have the "issues" with the blackhole, the trip from earth to planet A goes as it should. so . .. where protagonist should be 7 years old than her sister she is the same age. god does this even make any sense? also i don't want it to have to take a minimum of 4 years like ANGRY GUY said. haha. that sort of throws the entire thing off.. hmmmmm... damn.


It makes perfect sense. But a factor of nine for the differential would mean that the ship was going extremely fast, or the trip was longer than one year for the ship. If the ship were to take four years in shipboard time to get there and outside observers said that it looked like 10 years, then the Lorentz factor would be closer to possible. Take a look at the links I posted. I can't remember how to express what it would have to be. For a Lorentz factor the right side of the equation would be something like (t0-t1)/(sqrt (1-(v^2/c^2))), which isn't the right way to write it, but I don't have the right program now.

thisiskortny5
05-09-2016, 05:13 AM
Okay, I can work with that. I liked that sling shot idea, can we work with that?

Dennis E. Taylor
05-09-2016, 05:14 AM
According to my handy-dandy CalcLorentz program, if you want 1 year to go by for the occupants of the craft, and it's a nine light-year trip, your ship needs to be capable of constant 8.5 g acceleration. Which means you need some kind of acceleration compensation, or you'll have people pancakes.

For 9 Light Years at 8.5 G accel
Objective duration 9.23 years
Subjective duration 1.00 years
Top Speed 99.9694% c
Top Tau 40.41

thisiskortny5
05-09-2016, 05:58 AM
Is that that kind of acceleration compensations theoretically possible?

Dennis E. Taylor
05-09-2016, 06:15 AM
Is that that kind of acceleration compensations theoretically possible?

No, but then neither is 8.5 G acceleration/deceleration for 9+ years. Actually, if you're going to go the hard-SF route, then getting anywhere near that level of tau is out of the question.

OTOH, if you are positing an interstellar civilization, then really the only thing you have to assume is some kind of reactionless drive. Generally those are assumed to accelerate the whole ship equally, so no acceleration effects at all.

jjdebenedictis
05-09-2016, 07:16 AM
If you want to add in some hand-waving, you could have a faster-than-light drive of some sort and just have wonky time dilation effects as a side effect of that. It won't be hard science fiction anymore, but taking a year to get to a destination is already pushing the limit of what humans would think reasonable, and it's more likely we'd find a habitable planet faaaaaaar from Earth, not near it. So introducing warp speed or an Albucierre drive or something like that to circumvent the speed limit on the universe is a practical way for a novelist to make the time scales work.

You could also put your protagonist into cryogenic suspension for part of the trip to explain why she hasn't aged while her sibling has. No chemistry happens when you're frozen, so no aging.

thisiskortny5
05-09-2016, 07:39 AM
Okay. Going to have to give this some more thought. I'd like to keep it at least somewhat believable and not sound like a complete fool.

thisiskortny5
05-09-2016, 04:42 PM
OTOH, if you are positing an interstellar civilization, then really the only thing you have to assume is some kind of reactionless drive. Generally those are assumed to accelerate the whole ship equally, so no acceleration effects at all.

Can you explain to me what that means ^^^

Dennis E. Taylor
05-09-2016, 07:07 PM
Can you explain to me what that means ^^^

Reactionless drive doesn't spew hot gasses out the back in order to go forward. It uses some made-up (or just not-explained) method of accelerating the ship. Generally speaking, when novels have such a thing, it's just given a name and not otherwise discussed-- like:

At the captain's nod, the pilot reached over and activated the AngryGuy drive. The planet rapidly receded in the rear view as the ship accelerated out of the system.

And don't explain any more than that, unless you need time dilation effects. But I like JJ's hibernation idea better.

realityfix
05-22-2016, 07:29 AM
Just a thought of one writer to another. What about replacing the black hole with a worm hole? Work the plot so that the protagonist is enroute to Planet B from Planet A and an unstable wormhole suddenly opens up nearby. Their ship gets pulled to the entrance where they try reverse thrusters and all that but they fire some weapons into the entrance making the unstable wormhole collapse. Their ship's clock reports only so much time has passed but it is almost nine years back on Planets A and B. Black holes are messy harder to work with than wormholes.

jjdebenedictis
05-22-2016, 10:49 AM
Their ship's clock reports only so much time has passed but it is almost nine years back on Planets A and B. Black holes are messy harder to work with than wormholes.Actually, wormholes are arguably worse. :D

The problem is a wormhole is basically a black hole if you only get close to it. However, by collapsing it and turning it "off" before they fall into it, you could indeed cause them to have aged more slowly than Earth.

Be aware that when scientists talk about wormholes being unstable, they mean so unstable that they would collapse before anything could go through. Also, the size of wormholes is more likely to be subatomic-particle-sized than star-sized. So you're definitely well into space opera territory rather than science fiction, here, but yes, this could give you the situation you want. The unrealistic thing is now the wormhole's existence and behaviour rather than the time dilation.

Arcs
05-22-2016, 10:55 AM
Just have a 'higgs compensator', that removes all the higgs-bosons from everything. That way 8.5g acceleration would be painless.

But probably still physically confusing for the passengers.

A reactionless drive could function by collapsing reality in front of the ship and expanding it out the back, so that you move space instead of the ship. Therefore no acceleration at all.

realityfix
05-22-2016, 06:33 PM
My memory might be lagging here but maybe the OP should look into Herbert's "Dune" series if the OP wants to consider Arc's description of a possible reactionless drive. I believe they use a drug called "Spice" that actually gives the user the ability to move space as opposed to move themselves through space.

Telergic
05-22-2016, 07:46 PM
I agree if this is supposed to be hard SF there is no reasonable way to go fast enough to experience noticeable time dilation a la Tau-0, and also no reasonable way to survive a gravity field so intense as to cause time dilation a la Interstellar, no matter what Kip Thorne says. Because for the first you would go so fast that friction with the "medium" (ie radiation from random particles in deep space) destroys your ship, and for the second not only does such gravity not really exist anywhere, but even if it did it would be due to an ultra-massive super-gigantic black hole that would annihilate everything that comes near due to radiation from infalling matter. (Smaller black holes would destroy the ship due to tidal forces). In Interstellar the magical black hole exists because 5th-dimensional godlike beings made it that way, and so it is the very opposite of hard SF.

Of course rigorous hard SF can be rather boring for space operas, so if you break science in one controlled way -- a magical inertialess drive or frictionless force-field ship shields or whatever -- you may be able to come up with some way to be generally scientifically accurate in other respects and still have time dilation work in the story.

As an aside I believe the only plausible way for a spaceship to accelerate on its own faster than a tiny fraction of a G continuously over any great length of time is through the matter-antimatter reaction, which assumes some currently counterfactual means of accumulating enough antimatter.

King Neptune
05-22-2016, 09:54 PM
As an aside I believe the only plausible way for a spaceship to accelerate on its own faster than a tiny fraction of a G continuously over any great length of time is through the matter-antimatter reaction, which assumes some currently counterfactual means of accumulating enough antimatter.

It would be easier to make antimatter as needed, but still isn't something that can be done in significant quantities.

thisiskortny5
06-02-2016, 04:39 AM
So here is what i have decided on (Please tell me if i'm an idiot, because honestly i've done hours of research but still get a headache): planet A is New Earth in a different solar system. Planet B is another planet in that same solar system roughly the distance of what mars would be to our Earth. the aliens have made there trip to new Earth, picked up their passengers, and are now on their way back to Planet B. There is some sort of fail-safe built into the ship they're in. if they reach a certain velocity(for example from a black hole that could ... slingshot them???? someone help me when why they and how they could reach fast speeds, doesnt even have to be a black hole. id LOVE ideas other than the black hole thing just so i can have options) the fail-safe activates. the ship is built to withstand these speeds but because the human body is not, the fail safe is designed to "suspends them in an incompressible material" which preserves their body and stops them from aging. so they don't need to be going anywhere near 8.5 g but they do need to be going fast enough that it could be a danger to the passengers but the ship could be built to withstand the speeds.
thanks for everyone's help!

realityfix
06-03-2016, 03:16 AM
Okay, here is where I get stuck. Using your last post, about Planet A and Planet B being similar in location to one another and to their sun as our Earth and Mars, even using our current technology it would only be a year voyage one way. Using alien and or futuristic tech, that journey would be like going to the moon. Where I'm going with this is that the two planets are too close together to coexist with a Black Hole or to have one just suddenly open up. I think maybe I've missed something in your example .

Using another planet's gravitational field to "slingshot" is generally something done on purpose to gain the appropriate speed to reach an escape velocity, for example. It really isn't a maneuver done by accident. Perhaps you may have to increase the distance between Planet A and Planet B, like putting each one in a different solar system. That way, you would have some deep space distance where a Black Hole suddenly opens or a known Black Hole's gravity field is utilized for a slingshot maneuver to gain the acceleration needed to cross the open space between the two solar systems. Or, you can put it in your plot that the ship goes into a slingshot maneuver that goes awry and they end of out in deep space and off course. I'm sure you will figure it out as you seem like a determined writer (that's half the battle right there). Reply to this thread or leave me a PM if you want more ideas from me.

thisiskortny5
06-03-2016, 05:14 AM
Well what if there was no blackhole then? What if something else caused the ship to accelerate too quickly?? The blackhole thing is starting to give me a headache because I feel like it's too far fetched. So I need something that could accelerate the ship to high speeds so that the fail-safe has to activate and put them in a hibernation state.

realityfix
06-03-2016, 06:53 AM
If your plot needs an "accident" to activate the ship's fail-safe and put the crew and passengers into a hibernation state, I would go with the idea of the alien ship having to do a slingshot maneuver around the sun of the solar system of the planet they are leaving and an on-board computer glitch has the ship tossed into deep space where it encounters an asteroid field. The ship collides with an asteroid, the hull is breached, and the ship's automated systems put the people inside into protective hibernation and emergency lands the ship on one of the larger asteroids. With their radio damaged, the ship powered down to conserve power for the hibernation system, and a search party locating debris from the initial collision, the ship is listed by the authorities as missing or destroyed until an asteroid mining company discovers the lost ship. All of that should give you about nine years to play with. Let me know if tbis helps.

thisiskortny5
06-05-2016, 05:57 AM
Thank you. I appreciate you taking the time to help!

thisiskortny5
06-06-2016, 05:33 AM
Actually, wormholes are arguably worse. :D

The problem is a wormhole is basically a black hole if you only get close to it. However, by collapsing it and turning it "off" before they fall into it, you could indeed cause them to have aged more slowly than Earth.

Be aware that when scientists talk about wormholes being unstable, they mean so unstable that they would collapse before anything could go through. Also, the size of wormholes is more likely to be subatomic-particle-sized than star-sized. So you're definitely well into space opera territory rather than science fiction, here, but yes, this could give you the situation you want. The unrealistic thing is now the wormhole's existence and behaviour rather than the time dilation.


I'm going to bug you but feel free to ignore me :) Do you have any ideas, besides the blackhole, as to what would send the ship into high speeds that would activate some sort of fail safe, putting the passengers in the 'preserved' state? I guess it wouldn't have to be high speeds, but there needs to be a reason that would leave them absolutely no other options but to be frozen. some sort of danger, where they could get back to their planet on their own. i liked the high speeds because the frozen state would keep them from being crushed, but I'm not sure what would make the ship reach such a high velocity. Any ideas. Thank you!! :D

Dennis E. Taylor
06-06-2016, 05:54 AM
I'm going to bug you but feel free to ignore me :) Do you have any ideas, besides the blackhole, as to what would send the ship into high speeds that would activate some sort of fail safe, putting the passengers in the 'preserved' state? I guess it wouldn't have to be high speeds, but there needs to be a reason that would leave them absolutely no other options but to be frozen. some sort of danger, where they could get back to their planet on their own. i liked the high speeds because the frozen state would keep them from being crushed, but I'm not sure what would make the ship reach such a high velocity. Any ideas. Thank you!! :D

In The Gentle Giants of Ganymede, it was an internal issue. Something went wrong, and their journey back to our solar system took a couple million years longer than expected. Maybe you should go with an internal systems problem and some handwavium.

jjdebenedictis
06-06-2016, 07:52 AM
I'm going to bug you but feel free to ignore me :) Do you have any ideas, besides the blackhole, as to what would send the ship into high speeds that would activate some sort of fail safe, putting the passengers in the 'preserved' state? I guess it wouldn't have to be high speeds, but there needs to be a reason that would leave them absolutely no other options but to be frozen. some sort of danger, where they could get back to their planet on their own. i liked the high speeds because the frozen state would keep them from being crushed, but I'm not sure what would make the ship reach such a high velocity. Any ideas. Thank you!! :D

Read Wikipedia's article on "gravity assist" for an intro to how this works, but you want the ship to approach a massive body that is itself in motion, then get caught (gravitationally) by the body such that the ship performs a half-orbit around that body, and leaves the body from the other side of it, now heading in the same direction of the body. The speed of the ship gets boosted by roughly 2x the speed of the body.

So if it's a fast moving body, and massive enough to catch the ship gravitationally for just the right amount of time, then the ship might get a big boost from that.

You could have a rogue neutron star zoom through the solar system -- this is something utterly random and unusual. Neutron stars are very small and very dense, so they have powerful gravity (and also a powerful magnetic field). Most of the light they emit is in x-rays, so the star wouldn't necessarily be visible. Your ship presumably shields its crew well, so they hopefully will be safe from the hard radiation, but because a small runaway star is such a strange occurrence, the ship wouldn't necessarily be prepared for something like this.

The one thing that's a problem is that presumably astronomers have seen this star coming in the x-ray spectrum for a long while. They should be able to pinpoint where it is, how fast it's coming, where it will blow through the solar system, and how dangerous it will be to the inhabited planet(s). So you need to come up with a plausible reason for why no one involved in the transport of passengers knew about this.

Maybe the planets have no advanced astronomy yet. Maybe the shuttle-running aliens are practical joes who aren't on the lookout for things like this. Maybe they trust their computer systems, but the computer mistook the neutron star for a comet (a much more likely object to find zooming into a solar system), and thus didn't realize the gravitational wallop it would have. Something like that!