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small axe
09-08-2007, 07:06 AM
One often hears how "energy and matter are interchangeable" etc ... and I understand the part where stars fuse hydrogen into energy, bombs fuse plutonium into disturbingly loud bangs, etc ...

But I'm having a brain-lock at the moment, so can someone help here?

Could anyone give me a few real-world examples of energy spontaneously becoming matter?

I started to tell someone that the Big Bang was an example of that, but then I thought: well, can anyone back that up with anything but assumption and "theory" ???

We cannot say what form of energy existed pre-Big Bang until we work out the Theory Of Everything, right? No one understands how the cosmic forces and energies were unified, so we cannot use Big Bang as an example.

Is Vacuum Energy an example of matter being created from nothing, or is it just energy (and the example demands actual matter, some "we can build something out of this and use it as a paperweight" sort of matter)

So ... are energy and matter interchangeable in the real world, or does it just work nicely on a blackboard equation ... but doesn't seem to actually happen in the real world?

Anyone gots examples of energy-becomes-matter ???

Mac H.
09-08-2007, 07:32 AM
You aren't likely to find examples of energy spontaneously converting to matter here on earth.

The main reason is the ENORMOUS amounts of energy that is equivalent to a single gram of matter. Those amounts of energy aren't found easily.

It's amazing the things that occur in nature (we even have a natural nuclear reactor here in Australia) but I'd be surprised if you can find an example locally.

Mac

small axe
09-08-2007, 08:24 AM
You aren't likely to find examples of energy spontaneously converting to matter here on earth.


Oh, well, maybe I was too vague when I wrote 'real world example' ...

I mean, an example from anywhere in the Universe! Black hole stuff (Hawking radiation? Or is that still just theory and not demonstrated yet?) or any sort of cosmic event or some particle that exists longer than some annoyingly billionthof a billionth of a second before it stops, looks around, says "What the hell good is this reality?" and moves on to another universe? :)

It just chilled me to think I couldn't give an example of a scientific "fact" I'd never really questioned: if energy and matter are interchangeable, when did anyone ever see it happening in both directions? Never?

Anyway ... I just meant 'real world' in the sense of non-theory, I didn't mean to limit the examples to "occurring on planet Earth"

kdnxdr
09-08-2007, 08:30 AM
I know absolutely nothing about this sort of thing but I thought I would give it my best guess. The first thing that came to mind was volcanoes, maybe something to do with gases. The second thing that came to mind was a supercollider and how they can derive subparticles of matter from atoms, or am I making that up?

Hope you get some real answers.

kid

brer
09-08-2007, 09:05 AM
photosynthesis. (Think plants.)
And there are chemical processes that add energy to one set of molecules to convert them to another set.
And there are nuclear-type processes that add energy (photons) to like isotopes or stuff or like create something that has more total energy or something, err, I'm lost. sorry ... But then I'm always lost.


Could anyone give me a few real-world examples of energy spontaneously becoming matter?
Oh, sorry. I didn't answer your question. For some reason I thought you wanted an example of energy to matter conversion (i.e., photon absorption).

I guess you want something like those funny experiments where photons travel through a funny fog and then sometimes the photons disappear and there are a pair of short paths which indirectly indicate the temporary existence of charged particles, or something like that? Nope, I haven't a clue as to what I'm talking about. Yeah, I'm too lazy to google. ... nothing like a lazy Friday Night.

small axe
09-08-2007, 09:47 AM
Photosynthesis ... hmmm. Didn't think of that.

Would the physics-wise among us agree with that as being a useful example then?

Or is photosynthesis something more like using energy to convert one form of matter (rain, soil, etc) into another form of matter (flowers, sugars) that we eat and metabolize to grow our own bodies etc?

I was thinking more along the lines of a future science that could build its civilization out of sunlight (well, you know, some sort of high-hallucinatin' sort of sci-fi image ;)) ... but if you guys think photosynthesis is a valid example, that's cool too!

Is photosynthesis actually energy becoming matter, or just energy powering a change of matter into different matter?

Or am I losing myself in a false distinction there?

Anyway ... glad to hear more ideas or info about it!

brer
09-08-2007, 10:08 AM
photosynthesis = The process in green plants and certain other organisms by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source. Most forms of photosynthesis release oxygen as a byproduct.

Fine. I'm too tired to do anything meaningful. :)

photosynthesis basically "absorbs" photons, which is a form of raw energy, kinda. So the resulting molecules have more chemical energy. I guess. Whatca think, that sound kinda okayee?

Mass is a relatively stable way to store energy. A nucleus can absorb energy (photons) and thus increase in mass. Its mass (weight) increases. A proton plus an electron plus photons (energy) equals a neutron. i.e., A neutron has more mass than the sum of a proton plus an electron. So, a neutron has more "energy" than the sum of those other two ... and, err, ya can kinda get a fission if ya go far enough in that direction, when some of the "bonding" mass is converted back to energy (photons). i.e., "boom." A nuclear explosion via a fission bomb. (Ya kind get booms via a fusion process, too.)

Is this what ya looking for?

Careful. There a hawks on all lines. Men in bland outfits might visit ya now. Or men with funny english and bad hats might visit ya too. :eek:

brer
09-08-2007, 10:11 AM
Is photosynthesis actually energy becoming matter, or just energy powering a change of matter into different matter?

Yep. And, yep.

i.e., yes to both of your questions there.

brer
09-08-2007, 10:14 AM
Would the physics-wise among us agree with that as being a useful example then?

What's gym class got to do with this? :Shrug:

... err, just kidding. :D ... gym class is physical education class is "Phyz-Ed Class" is physics class ... yeah, bad joke. sorry.

brer
09-08-2007, 10:22 AM
Or is photosynthesis something more like using energy to convert one form of matter (rain, soil, etc + CO2 ) into another form of matter (flowers, sugars) that we eat and metabolize to grow our own bodies etc?

Yea, I guess ya could think of it like that. That animals basically convert high energy types of matter into low energy types of matter, and that process (mostly chemical) releases energy which we need to power ourselves.

Plants do the opposite. They convert low energy types of matter, by combining them with photons (energy, which could be sunlight), and thus produce the high energy types of matter, which we animals need--see above paragraph.

Well, kinda, generally, this post is kinda true. ...
(... but, but .... a little voice says, but, proteins are a source of high energy, ain't them better than plant food? Get lost little voice, get lost.)

DocBrown
09-08-2007, 12:05 PM
Using sunlight in the photosynthesis process to create matter seems a bit suspect in terms of creating energy into matter, but I am no biologist so I have no counterargument if people seem to think that is the case. I just don't know enough about the process to be able to tell for sure.

I am surprised that everyone has missed the obvious in terms of transferring matter into energy, i.e. Radioactive decay.

Isotopes release electromagnetic energy when the nucleus breaks down into simpler elements.

EDIT: OOPS! Sorry, it is late. I misread the title and original post. I thought people were looking for both energy to mass and mass to energy examples.

EDIT 2: Upon further consideration, since matter and energy are interchangeable, if you want an example of energy being converted to mass you don't really need to look any further than your stove top. Heating up a pan will increase the temperature and thus increase it's mass as well.

To see this, merely pretend the pan is a closed system and recognize that as you add heat you're increasing the total energy of the pan. Since matter and energy are interchangeable the mass must also increase. Of course, it would be on a scale far too small to measure, but the mass would nonetheless increase.

oscuridad
09-08-2007, 12:27 PM
put enough energy into some matter and it will liberate into more energy - striking a match for example

Mac H.
09-08-2007, 01:16 PM
Heating up a pan will increase the temperature and thus increase it's mass as well.

To see this, merely pretend the pan is a closed system and recognize that as you add heat you're increasing the total energy of the pan. Since matter and energy are interchangeable the mass must also increase. Of course, it would be on a scale far too small to measure, but the mass would nonetheless increase.This isn't right. Being able to convert one from the other means that you can CONVERT one from the other - you don't have both at once. So if you could easily convert the energy (from the pan's heat) into matter - you wouldn't have the thermal energy anymore - it would be CONVERTED into matter. Sure, you could start quoting energy in 'grams' (which is effectively what the unitless 'natural' system does, where E=M) but it doesn't mean much.

In particle colliders, of course, we can convert energy into mass - but making a stable atom is more than just pumping energy into it ... which means that particles (or sub-particles) created last just fractions of a second.

If you want details, juts google 'Energy to Matter conversion'.

Good luck,

Mac
(PS: Unfortunately, the match example above is also wrong - it isn't a matter to energy conversion, just a chemical reaction)

DocBrown
09-09-2007, 06:10 PM
Actually, you're right Mac H., I was thinking in more general terms.

Being a mathematician my view on physics needs to be corrected from time to time. I read through some material and I am now convinced that, for now, energy to matter outside of very specific conditions, is not a natural process. Which again, shows that people need to be careful when applying mathematics to real life examples. It is actually quite common for simple mathematical ideas to be used to describe something, but then something else that does not have a simple physical explanation creeps into the theory because it is valid mathematically.

benbradley
09-10-2007, 01:42 AM
Photosynthesis ... hmmm. Didn't think of that.

Would the physics-wise among us agree with that as being a useful example then?

Or is photosynthesis something more like using energy to convert one form of matter (rain, soil, etc) into another form of matter (flowers, sugars) that we eat and metabolize to grow our own bodies etc?

I was thinking more along the lines of a future science that could build its civilization out of sunlight (well, you know, some sort of high-hallucinatin' sort of sci-fi image ;)) ... but if you guys think photosynthesis is a valid example, that's cool too!

Is photosynthesis actually energy becoming matter, or just energy powering a change of matter into different matter?

Or am I losing myself in a false distinction there?

Anyway ... glad to hear more ideas or info about it!
It's my understanding that ALL "stored" energy manifests itself as an increase in mass. Some chemical reactions release energy (burning is a classic example), and the total mass of the resulting chemicals (the CO, CO2, the ash) is less than the original materials (oxygen and wood, for example). Likewise, other chemical reactions absorb energy, and this increases the mass. This went on unnoticed for centuries because the amount of mass change is too small to be detected. I think under the right conditions with careful measurement it could perhaps be detected (I vaguely recall reading about this being done with a seed in a sealed glass environment, then with the resulting plant several months/years later), but generally, the mass change is way too small to be measured.

Nuclear reactions have a more noticable mass change because the energy involved vs. the total mass is so much greater. A uranium atom splitting/decaying into smaller atoms loses something like a tenth of one percent of its mass. Hydrogen fusing into helium (as in a Hydrogen bomb or in the center of the Sun) is much more energetic, and the resulting helium (all of these are rough figures, from my memory from many years ago) has about three percent less mass than the original hydrogen. The collision of matter and antimatter (which is real, but only extremely small amounts have been generated in particle accelerators) causes a 100 percent conversion of matter to energy.

To answer this: Is photosynthesis actually energy becoming matter, or just energy powering a change of matter into different matter? I think the answer is both. And yes, a spring under tension has more mass than the same spring without tension, because it has had energy added to it. Unfortunately, the change in mass of a typical spring is probably in the 14th decimal place, far less than the best scales can resolve. You can use Einstein's famous equation to calculate how much energy becomes how much mass, but I don't know what units to use or exactly how to do it offhand. I just know it takes a heck of a lot of energy to make a small amount of change in mass.

oscuridad
09-10-2007, 02:38 AM
(PS: Unfortunately, the match example above is also wrong - it isn't a matter to energy conversion, just a chemical reaction)

I was being a bit facetious - I did not mean that this was a conversion - otherwise I guess just stepping outside to light a cigarette would not be sufficient to protect the health of your co-workers...

Pthom
09-10-2007, 04:33 AM
the match example above is ... just a chemical reaction)Once it's started, yes, but there in order for that to take place, energy has to be injected into the system--by rapidly rubbing the match head along the sand paper. Mechanical energy (friction) —> heat —> chemical reaction.

At least, I'm pretty sure that's the situation. :)

Mac H.
09-10-2007, 05:32 AM
It's my understanding that ALL "stored" energy manifests itself as an increase in mass.That is wrong. I'm sure there is some bad science book somewhere which has claimed it, but it is totally wrong.
Consider an example - I have a metal lump on a precision scale.

I turn on an electromagnet nearby - the metal lump now has more 'potential energy' - because, if released, it will move in the magnetic field towards the electromagnet, gaining kinetic energy.

So, in this thought experiment, the scale should show an increase in mass.

However, the AMOUNT of potential energy doesn't just depend on the strength of the magnetic field where the metal lump is - it depends on the distance the magnetic field extends to before the lump will collide with the magnet. Since there is no way for the metal lump to 'know' how far the field extends, there is no way for it to 'know' how much to increase the mass by.

Despite the fact we talk about the potential energy of an object - it is NOT actually a property of the object. It is a calculation about the remote environment as well as the object itself.


A spring under tension has more mass than the same spring without tension, because it has had energy added to it.Again, no.



Unfortunately, the change in mass of a typical spring is probably in the 14th decimal place, far less than the best scales can resolve. You'd be suprised.

While George Washington was president, a scientist named Cavendish was measuring the amount of gravity between two lead balls. He had to do it with a telescope outside of the building so he didn't stuff up the measurements.

Mac

Jamesaritchie
09-12-2007, 07:16 PM
If I remember correctly, our bodies turn matter into energy when we eat, but also turn this energy into matter as we grow.

JimmyB27
09-13-2007, 04:18 PM
If I remember correctly, our bodies turn matter into energy when we eat, but also turn this energy into matter as we grow.
I'm reasonably certain this is wrong. As someone mentioned up-thread, the amount of energy you get out when you transform matter is very large. Consider Einstein's famous formula e=mc˛, where e is the energy in joules, m is the mass in kg and c is the speed of light in m/s.
So, you eat one kilo of food, and we get e = 1 x 299,792,458˛. Which means that, if we are turning matter into energy, the total energy we get from one kilo of food is 89875517873681764 joules, or some 90,000 terajoules. We're talking nuclear explosion territory here.
As I understand it, what our bodies are doing when we eat is actually converting energy that is already energy into a different type of energy. We take the chemical energy stored in the food and convert it, ultimately, into kinetic energy, heat and electrical energy.
Here's an article about an experiment attempting to create matter from energy.

PS - This is all a mixture of back-of-the-envelope science and stuff I remember from books and school. In short, I may be wrong :)

DocBrown
09-13-2007, 04:39 PM
If I remember correctly, our bodies turn matter into energy when we eat, but also turn this energy into matter as we grow.


No. No nuclear reactions occurring within the body. The processing of food is transferring chemical energy to thermal energy and electrical energy and so much more, but no nuclear creation or destruction of matter.

Ordinary_Guy
09-15-2007, 11:23 PM
Lots of interesting observations here...

Now, I'm no physicist – I don't even play one on TV – but you might want to consider a few things as you contemplate "matter replicators" or other Star Trek-style doohickies.

We can start with Old Faithful: E=mc2. Energy (in the big "E" joules) is equivalent to matter (in kilograms) times the speed of light, squared. Cool, right? We're all comfortable with that one? QFT?

If we actually pry into that equation, we realize that it's definitely not E=m. It's not a 1=1 formula. In fact, in order for energy to have become matter in the first place, it had to have a great deal more energy poured into it (hence the "c2"). If you need to know more about the whole "speed of light" thing, check out this article (http://www.osti.gov/accomplishments/nuggets/einstein/speedoflight.html)...

What does this mean for your writing (and, for that matter, the world around you)?

It means it's a lot easier for matter to create energy than the other way around. Even when matter does create energy, it's usually only the tiniest slice being released. A fission reaction (as in "from a bomb") releases only 0.1% of plutonium's mass in the split. FYI: fusion releases only 0.5%. These are pretty big bangs.

Going the other direction is even more difficult. Even nucleosynthesis is stars isn't really creating matter from energy, it's adding energy to lighter forms of matter (hence "fusion" and not "creation").

Where, realistically, could that much energy come together to form matter? That I'm not sure, though "the Big Bang" may well have been it. On the bright side, that was a whole lotta matter and should be able to tide us over a while.

...That doesn't mean this that E=mc2 is only theory, though: experiments at the SLAC did in fact create something from effectively nothing in 1997 (http://www.sciencedaily.com/releases/1997/09/970918045841.htm) (unlike creating something from nothing in politics, which has been happening for as long as man has existed). Note, though, that a humongous amount of energy was poured into it and only a wee little particle came out of it.

End conclusion: creating matter from scratch is not trivial. Not impossible, but definitely not trivial.

small axe
09-21-2007, 03:08 PM
Thanks for all the info and thoughts and discussion, everyone!

I followed up on some of the research some of you suggested, and one of the tidbits I ran across (though now I'm wondering if I wasn't delirious and imagined I read it, or rather dreamt I read it) was the statement that all of the energy our Sun produces, if converted back into matter, wouldn't add up to the mass of a cheeseburger.

Not surprisingly, hearing that confused me again (and now I cannot find that article again to re-read it) :)

I suppose talk like that would've gotten Galileo into deeper trouble with both the Church (who, let us remember, basically sentenced him to go home and stay there and eat cheeseburgers) and the cutting-edge Scientific crowd who thought the Universe revolved around the Sun attached to perfect crystal spheres!

Anyway ... thanks for the interesting ideas!

Red Robin
09-22-2007, 05:02 AM
If we actually pry into that equation, we realize that it's definitely not E=m. It's not a 1=1 formula.

I'm not sure what you mean here. E=mc2 is a linear equation. The c is a constant, so double the m and you double the E.



Where, realistically, could that much energy come together to form matter?

I've heard some people propose that in the future we will be able to aim hundreds of high energy lasers at the same point in space, and the energy density will be so high that matter and anti-matter will be produced. In that way we could produce anti-matter fuel.

I can't find any references for that, unfortunately.

Higgins
09-26-2007, 05:23 PM
One often hears how "energy and matter are interchangeable" etc ... and I understand the part where stars fuse hydrogen into energy, bombs fuse plutonium into disturbingly loud bangs, etc ...

But I'm having a brain-lock at the moment, so can someone help here?

Could anyone give me a few real-world examples of energy spontaneously becoming matter?

I started to tell someone that the Big Bang was an example of that, but then I thought: well, can anyone back that up with anything but assumption and "theory" ???

We cannot say what form of energy existed pre-Big Bang until we work out the Theory Of Everything, right? No one understands how the cosmic forces and energies were unified, so we cannot use Big Bang as an example.

Is Vacuum Energy an example of matter being created from nothing, or is it just energy (and the example demands actual matter, some "we can build something out of this and use it as a paperweight" sort of matter)

So ... are energy and matter interchangeable in the real world, or does it just work nicely on a blackboard equation ... but doesn't seem to actually happen in the real world?

Anyone gots examples of energy-becomes-matter ???

Oddly enough, all of the examples in this thread so far are energy to energy conversions, except for Fusion processes in the Sun. Energy to matter conversion happens in processes (more or less by definition) in the atomic to subatomic range and not at the molecular level (eg. photosynthesis, which just re-arranges photon energy into molecular bond energy)

Energy to matter conversions are common and happen in stellar/solar fusion and also in particle colliders on earth and in thermonuclear bombs.

A nicer, more everyday example happens when a powerful packet of electromagnetic radiation (photons of a very short wavelength) as in

http://science.nasa.gov/NEWHOME/headlines/ast02sep98_1.htm

hits something.


Some aspects of the Big Bang are very well known and the Standard Model works well enough to explain the cosmic abundance of Helium and possibly some Lithium isotopes:

http://kicp.uchicago.edu/~odom/compton_files/compton_lecture_01_handout.pdf

Higgins
09-26-2007, 06:40 PM
Thanks for all the info and thoughts and discussion, everyone!

I followed up on some of the research some of you suggested, and one of the tidbits I ran across (though now I'm wondering if I wasn't delirious and imagined I read it, or rather dreamt I read it) was the statement that all of the energy our Sun produces, if converted back into matter, wouldn't add up to the mass of a cheeseburger.

Not surprisingly, hearing that confused me again (and now I cannot find that article again to re-read it) :)

I suppose talk like that would've gotten Galileo into deeper trouble with both the Church (who, let us remember, basically sentenced him to go home and stay there and eat cheeseburgers) and the cutting-edge Scientific crowd who thought the Universe revolved around the Sun attached to perfect crystal spheres!

Anyway ... thanks for the interesting ideas!

Here's something on Solar fusion:

http://www.tim-thompson.com/fusion.html

And Galileo didn't have so much of a problem with the cutting-edge crystal sphere crowd
since Copernicus had already started on breaking up that image of the cosmos and the crystal spheres were no longer cutting-edge science.

dobiwon
09-26-2007, 11:11 PM
Energy will transform into matter as something of finite mass approaches the speed of light. Here is an example with electrons:
Inside the Advanced Light Source, electrons are boosted up to a very high kinetic energy of 1.5 billion electron volts (1.5 GeV). During the very early part of this energy boost, the electrons are in the speed range covered by Newtonian physics, and most of their
gain in kinetic energy comes from speeding up. As the electrons approach the speed of light, they move into the relativistic regime, and successive energy boosts produce more change in the electrons’ masses than in their speeds.

Here's the link (http://lbl.gov/MicroWorlds/teachers/massenergy.pdf).

Popeyesays
09-26-2007, 11:12 PM
I'm not sure what you mean here. E=mc2 is a linear equation. The c is a constant, so double the m and you double the E.




I've heard some people propose that in the future we will be able to aim hundreds of high energy lasers at the same point in space, and the energy density will be so high that matter and anti-matter will be produced. In that way we could produce anti-matter fuel.

I can't find any references for that, unfortunately.

It's not e=mc2, it's e=mc(squared). Square 186,000 kilometers per second and see what you get. It's somewhat larger than doubling.

Regards,
Scott

Jeff Colburn
09-26-2007, 11:58 PM
Supernova. When a star goes supernova it creates the heavier elements found on the periodic table, like gold. Most heavy elements are formed this way.

Have Fun,
Jeff

dobiwon
09-27-2007, 12:35 AM
It's not e=mc2, it's e=mc(squared). Square 186,000 kilometers per second and see what you get. It's somewhat larger than doubling.What RedRobin says is true--E is proportional to m--if m is doubled, then E is doubled. No matter what though, E is always c-squared times as big as m.

oscuridad
09-27-2007, 01:33 AM
Supernova. When a star goes supernova it creates the heavier elements found on the periodic table, like gold. Most heavy elements are formed this way.
Jeff

ALL heavy elements are formed in this way. We are stardust, man.

blacbird
09-27-2007, 02:52 AM
Supernova. When a star goes supernova it creates the heavier elements found on the periodic table, like gold. Most heavy elements are formed this way.

But it doesn't create these heavy atomic nuclei out of energy. It creates them through forced fusion of protons and neutrons already in existence as part of the stellar mass.

caw

benbradley
09-27-2007, 04:01 AM
But it doesn't create these heavy atomic nuclei out of energy. It creates them through forced fusion of protons and neutrons already in existence as part of the stellar mass.

caw
It's both, though of course the vast majority of 'stuff' in an atom is still the protons, neutrons and electrons. But the total mass of an atom is DIFFERENT form the sum of its subatomic particles' separated, individual masses.

Here's a Google search applicable to my earlier post. I just KNEW I wasn't imagining this stuff - I should have paid a little more attention in chemistry and physics classes, I might have remembered these keywords:
http://www.google.com/search?q=%22binding+energy%22+%22mass+defect

Most links discuss only nuclear binding energy, as the change in mass is more significant with atomic/nuclear reactions because they involve so much more energy change per unit mass than do chemical and mechanical interactions. But a few of the links do discuss binding energy and mass defect as related to other forces and systems, such as the Wikipedia entry, and this link:
http://www.egglescliffe.org.uk/physics/relativity/binener.html

blacbird
09-27-2007, 09:55 AM
It's both, though of course the vast majority of 'stuff' in an atom is still the protons, neutrons and electrons. But the total mass of an atom is DIFFERENT form the sum of its subatomic particles' separated, individual masses.

Yes, of course, although the amount of energy transformation is very, very small, as you have implied. My main point was that supernovas do not just transform raw energy into new heavy atomic nuclei.

caw

Jeff Colburn
09-27-2007, 11:31 AM
Here's something I just found.

Question - If matter can be "converted" to energy, as suggested by
the theory of relativity, can energy be alternately "converted" to
matter? what conditions are needed to carry out this process?
Also.. if particles could be created by this process, is there a way to
form matter that is stable? Or would all matter formed thus be prone to
>decay?
>
>Yes. This happens all the time in the target area of a particle
>accelerator. Both stable and unstable particles can be made in this
>way. You always make particle-antiparticle pairs, so you need energy
>equivalent to twice the rest mass of a particle to get anything.
>
>Tim Mooney
================================================== =======
>Matter can be formed from energy.
>
>One example of this is reverse beta-decay. If an electron, an
>anti-neutrino, and a proton come together with enough kinetic energy, they
>may join into a neutron. The neutron has more mass than the original three
>particles. If the neutron is within an atom, it may stay put.
>
>A more dramatic example is the stream of particles that come from a nuclear
>explosion. Much of the original mass turns into energy. Afterwards some of
>the energy turns into mass, many of them particles that did not exist within
>the original nuclear fuel.
>Mellendorf
================================================== =======
>No, once matter is converted to energy, it is used. Energy is converted
>into mechanical or electrical energy or just lost to the atmosphere as heat
>energy. This is why there are people trying to figure out new forms of
>energy -- because fossil fuels and the like will eventually run out.
>Katie Page

Have Fun,
Jeff

Jeff Colburn
09-27-2007, 11:33 AM
And check this out.

http://leiwen.tripod.com/create_matter.htm

Have Fun,
Jeff

Jeff Colburn
09-27-2007, 11:37 AM
And look here too.

http://imagine.gsfc.nasa.gov/docs/teachers/lessons/xray_spectra/background-elements.html

Have Fun,
Jeff

MargueriteMing
11-10-2007, 04:11 PM
http://www.amazon.com/Charm-Strange-Quarks-Mysteries-Revolutions/dp/0387988971/ref=sr_1_1?ie=UTF8&s=books&qid=1194695961&sr=8-1

Absolutely the BEST book I've read to date for someone who is looking to understand the concepts, without all the intense math. It traces the growth of knowledge of particle physics from the late 1800s. It explains the history and development of the Standard Model, the current theory of the structure of matter, in a way that is accessible to anyone who has a bit of science background, without bogging down in lots of math.

MargueriteMing
11-10-2007, 05:20 PM
I'm not sure what you mean here. E=mc2 is a linear equation. The c is a constant, so double the m and you double the E.




I've heard some people propose that in the future we will be able to aim hundreds of high energy lasers at the same point in space, and the energy density will be so high that matter and anti-matter will be produced. In that way we could produce anti-matter fuel.

I can't find any references for that, unfortunately.

Anti-matter is created routinely in supercolliders.

benbradley
11-10-2007, 06:09 PM
I'm not sure what you mean here. E=mc2 is a linear equation. The c is a constant, so double the m and you double the E.
Yes, it is a linear RATIO, but the earlier poster's point is that the C constant is big, and it's actually C squared, so it takes a huge amount of energy to make a little bit of matter, and conversely when you convert a little bit of matter to energy you get a huge amount of energy.


I've heard some people propose that in the future we will be able to aim hundreds of high energy lasers at the same point in space, and the energy density will be so high that matter and anti-matter will be produced. In that way we could produce anti-matter fuel.

I can't find any references for that, unfortunately.

And apparently the energy available in the antimatter will be no more than then energy used by the lasers to generate it, much like electrolysis to get pure hydrogen from water, you're just converting "energy" from one form to another. But of course, antimatter is much denser than anything else as far as the amount of energy it generates when combining with ordinary matter (pro-matter?). Just drop a fraction of an ounce onto any major city...

lpetrich
11-10-2007, 09:38 PM
I'd like to know what "small axe" is counting as energy and matter.

But from what I'm guessing that he's thinking of, particle accelerators and cosmic rays do it all the time. Particle accelerators or "atom smashers" give elementary particles a lot of kinetic energy, and when they collide, the result is often a big shower of particles, whose mass-energy and kinetic energy all came from the original particles' kinetic energy.

Doug Johnson
11-10-2007, 10:05 PM
The amount of mass created is e/c squared.

c squared is a huge number. When you divide a huge amount of energy by c squared, you get a tiny bit of mass.


If you double the amount of energy, you double the amount of mass, but it's still a small amount of mass.

Final point. Writers shouldn't talk about math.

Ruv Draba
04-10-2008, 07:00 AM
A lot of posts in this thread are old, but it might be worth clearing up some confusion... This stuff is from my old University physics and chemistry days...

Scientists normally distinguish chemical change from physical change, and neither of these is what we need to create matter from energy, but they're a good starting point, so here they are:

Chemical change: a change that produces a new substance. Burning wood changes molecules of wood into molecules of smoke. Eating food changes molecules of food into molecules of people. You can tell when a substance is new because it acts differently in contact with other substances. Photosynthesis is an example of chemical change.

Chemical changes often either consume energy (e.g. baking bread) or produce energy (e.g. burning wood), but the energy that goes into these changes is normally locked in the molecule. One principal of chemical changes is that the total amount of mass doesn't change. If you burn a tonne of wood you will produce a tonne of wood-smoke, ash and steam. If you eat a half-pound meal then you'll gain weight by half a pound (less whatever what you excrete)

Physical change:a change that alters the physical properties of a substance, but keeps the chemical properties. Cutting a log into sawdust doesn't stop the sawdust from acting like wood (it'll still burn, for instance, and termites will still eat it). Freezing or boiling water doesn't make it poisonous to us. Physical changes often either consume energy (e.g. boiling water), or release energy (e.g. a hot oven cooling). The total mass of substances undergoing physical change doesn't alter either. Freeze 1kg of water and you get 1kg of ice (except for some air bubbles that escape while you're freezing it, but these add up to the total).

Point is: neither physical nor chemical changes are an example of energy converting into matter - because the total mass of the substances doesn't change.

For our purposes, energy only converts into matter with great difficulty, and only in tiny quantities. The most common way this occurs on Earth is via a particle accelerator (http://en.wikipedia.org/wiki/Particle_accelerator), where small particles of matter are smashed together at high speed (the energy is in the speed), to produce more particles of matter that actually weigh more than the original particles. If you can imagine a high-speed smash between two Minis that manages to produce an SUV and two bicycles, that's pretty much what scientists are trying to do with particle accelerators.

Unfortunately, these collisions don't produce even a single atom (http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970724a.html) -- just fragments of atoms. And you can't really 'aim' one single particle at another - you have to fling a lot together and hope that a few of them crash together in the right way. Then you find a clever way to whisk away the original, light particles, and see if there are any heavy ones left.

What does this mean for the universe?

Well, it's all speculative, but here's a popular view:

Whatever created all the matter in our Universe, it was an extraordinary event, and it seemed to happen all at once. A lot of matter was created and flung outward with a lot of excess energy. This matter collided and made more matter, and eventually made atoms which were heavy enough to combine into molecules, which got big enough to attract one another through gravity. This matter is still flying apart. Last time I read anything on this, the idea was that it would keep flying apart (http://www.xenophilia.com/str_space_univ.htm)-- never to come back together and explode again.

If that happened, then eventually galaxies would move so far apart that we couldn't see them, and so the night sky would lose most of its stars. I'm not sure what would happen to our own galaxy - would it fly apart, or get pulled back in to smash together again? If the latter, it might create some more matter, but it's not the sort of thing you could see from earth, because our solar system would get mooshed to atomic paste too.

So, no Instaburgers?

Back to Science Fiction and Instant Mass, the energy-mass equation (E = mc2) is not your friend if you want to turn electricity into a hamburger, say - even if you had machinery clever enough to do it. Converting a single sugar cube into pure energy could light a small city for a whole year, so to get the sugar cube back, you'd have to drain that city's lighting for a year. And nanotechnology won't help you get a sugar-cube rather than atomic paste, since nanotech is made of big molecules, and we're talking about assembling splinters of a single atom.

If you want instant food, you're much better off assembling it from existing molecules - via chemical change. That's essentially what nanotech is meant to do - just the same thing we do in a kitchen or a chemistry lab, only on a smaller scale and with more efficiency.

Hope this helps. :D

benbradley
04-10-2008, 09:20 AM
...
Final point. Writers shouldn't talk about math.
Then only non-writers should talk/write about math? Maybe that explains some of the math books I've read...

A lot of posts in this thread are old, but it might be worth clearing up some confusion... This stuff is from my old University physics and chemistry days...

Scientists normally distinguish chemical change from physical change, and neither of these is what we need to create matter from energy, but they're a good starting point, so here they are:
If by "creating matter" you mean making atoms or even subatomic particles, yeah, that's not gonna happen with physical or chemical changes. And as discussed, that usually doesn't even happen with most nuclear changes. But any change that increases or decreases the amount of energy in the system DOES change the mass (by, of course, a very, very small amount).

Chemical change: a change that produces a new substance. Burning wood changes molecules of wood into molecules of smoke. Eating food changes molecules of food into molecules of people. You can tell when a substance is new because it acts differently in contact with other substances. Photosynthesis is an example of chemical change.

Chemical changes often either consume energy (e.g. baking bread) or produce energy (e.g. burning wood), but the energy that goes into these changes is normally locked in the molecule. One principal of chemical changes is that the total amount of mass doesn't change.
For (almost?) all practical purposes and to the limits of most (all?) mass measurements we know how to do that's true, but theoretically the mass DOES change (by of course a very slight amount), even though the total number of atoms and subatomic particles does not change. Re-read my other contributions to the thread, or research Mass Defect. It's not just for nuclear reactions anymore.;)

Ruv Draba
04-10-2008, 09:57 AM
If by "creating matter" you mean making atoms or even subatomic particles, yeah, that's not gonna happen with physical or chemical changes. And as discussed, that usually doesn't even happen with most nuclear changes. But any change that increases or decreases the amount of energy in the system DOES change the mass (by, of course, a very, very small amount).Well, that's interesting and thank you for it, but it's kinda infinitesimally pernickety too.

When I posted I was already aware of the ministichiscule (technical term!) mass effects of capturing photons, say... and the Mass Deficit effect you mention (yes, I did look it up!) is smaller than that still for molecular bonds... So it might be pushing the point too far into theory-land to worry about systemic 'mass deficits' from cutting your steak before you eat it (I certainly won't be wolfing mine whole to avoid steak-loss!). I think you'd get more mass loss from losing infrared photons as your steak cools -- and that's immeasurable compared to the mass loss from the steam, say. (Eat your steak frozen with your head in a plastic bag if you want to maximise the experience!). :D And let's not talk about the relativistic mass effects of throwing the steak down your throat at near light-speed (feels like more steak, but adds no calories - and you have to eat it blue!)

Think I'll stick with 'Conservation of mass' for most purposes. It's easy to explain and understand and durnit we know that when you add 200mls of milk to 0.5kg of flour, you get 0.7kg of cake batter, and zapping it with electricity won't give you 0.75kg! :D:D:D

(Oh, and since when did Catslave and me become the same person? One of us should be offended at least!! :D :D)

PiggyGirl
04-11-2008, 01:01 AM
I thought the whole idea behind the "Big Bang" was energy turning into matter.

kullervo
04-11-2008, 04:31 AM
Wow, there's a bunch of wrong in this thread.

1. Energy is converted into matter inside particle accelerators. But do to the conservation laws of particle physics, matter/anti-matter pairs are created and destroyed in tiny fractions of a second.

2. Supernovae and fusion do not create new matter. They simply combine simpler atoms into more complex atoms.

3. Photosynthesis does not create new matter. It lends energy to the process by which plants create sugars.

4. Nothing can be said of anything "before" the Big Bang. Energy, matter, spacetime, and all physical laws came into being at that moment. As time started at the Big Bang, there was no such thing as "before."

benbradley
08-03-2008, 05:08 AM
I just saw an "article" that reminded me of this old thread...glancing through it again, now I recall that it was a bit cantankerous...

Wow, there's a bunch of wrong in this thread.
Whoa, that appears a bit accusing and unneccesary. If you feel that way It might be better if you responded to each statement you see as wrong with a correction (yeah, perhaps a lot of work), that way we ignorant people can at least learn from you. But anyway...

1. Energy is converted into matter inside particle accelerators. But do to the conservation laws of particle physics, matter/anti-matter pairs are created and destroyed in tiny fractions of a second.
This is exactly what brought this thread to mind - this "article" says energy is converted to matter and antimatter in equal amounts, just as presumed to have happened in the Big Bang, but mysteriously since then, the parts of the Universe we can test are virtually 100 percent matter with no antimatter.

So with that, here's the article:
http://www.newscientist.com/blog/shortsharpscience/2008/07/rappin-physics.html
Here's another version on a page with more commentary, but this one has the volume going up and down:
http://www.boingboing.net/2008/07/31/large-hadron-rap-bes.html

Lhun
08-07-2008, 02:17 PM
Wow, there's a bunch of wrong in this thread.

1. Energy is converted into matter inside particle accelerators. But do to the conservation laws of particle physics, matter/anti-matter pairs are created and destroyed in tiny fractions of a second.
You're thinking vacuum fluctuations here. Particle pairs that are created via collision (in contrast to those just popping into existence) can persist longer.

2. Supernovae and fusion do not create new matter. They simply combine simpler atoms into more complex atoms.
Elements created by fusion have a (ever so slightly) different mass than the two elements fused. So, strictly speaking supernova fusions do create matter.

Prozyan
08-07-2008, 03:34 PM
4. Nothing can be said of anything "before" the Big Bang. Energy, matter, spacetime, and all physical laws came into being at that moment. As time started at the Big Bang, there was no such thing as "before."

This isn't exactly accurate, either.

First, it is important to keep in mind that when astronomers think about the Big Bang, in general, they are not thinking about the actual event itself. Rather, they are thinking about the model used to describe what happened afterward. It is important to keep that in mind, as current math cannot calculate to t=0. To try, you get things like zero volume and infinite density of matter and energy. It’s not that this moment didn’t exist physically, or that something impossible happened, it’s just that the math we currently use can’t describe it. Indeed, the closer you get to t=0, the more the math breaks down.

What happened beginning a nanosecond after the event can be modelled fairly accurately. But the event itself, and even before the event? The way our math works, it doesn't make sense. The basic problem is the non-unification between Einstein's relativity, which gives us a good idea how certain things work (like large-scale gravity) and quantum mechanics, which gives us a good idea how other things work (like particles) but no one has been able to combine the two. And, without that combination, it is impossible to model the occurance of the Big Bang or anything before that point. However, that is changing and we are starting to see plausible theories of what there was prior to the Big Bang.

I'd encourage you to look into Loop Quantum Gravity, and into the research being done by Martin Bojowald: http://www.science.psu.edu/alert/Bojowald6-2007.htm

Brane Cosmology also provides several other theories about what existed prior to the Big Bang.

To simply state that nothing existed before the Big Bang and therefore any study of what was before the Big Bang is pointless as you did is completely incorrect.

ShadowFox
08-07-2008, 03:55 PM
This isn't exactly accurate, either.
.


In the natural universe, the only situation I know of where it is really arguable that energy is consistently converted into matter is at the event horizon of a black hole, where hawking radiation is produced from potential energy. Even then, many people think it is actually the conversion of matter into energy :shrug: .

Bartholomew
09-08-2008, 09:51 AM
How about when people absorb sunlight and get their vitamin D? Does that count as a real world example?

Pthom
09-08-2008, 11:31 AM
Sunlight radiation causes a chemical reaction in the skin that converts other substances into Vitamin D. The energy is a trigger (like turning on the burner on your cooktop to caramelize onions), not the source of the vitamin.

Bartholomew
09-09-2008, 05:04 AM
I guess I just didn't understand the question.