Link between Thermo and Special Rel?

[magic_claw93]

Link between Thermo and Special Rel?

Ok, here's the situation: my friends and I were having a sleepover, and right before we slept, we started to talk about physics (lol... what nerds we are...). I began by saying, what if we achieve absolute zero. My friends said, we already achieved absolute zero, and that space is absolute zero due to the absence of matter (which is wrong; go me!). I also asked my chemistry teacher what will happen as we approach absolute zero, and he told me that the vibration will stop. I asked the teacher, what "theoretically" happens at zero, and he told me that the vibrations will stop, but the atoms will continue to rotate to prevent itself from reaching zero (kind of like light speed, space slows down so that you don't pass it).

My question is: If we DO manage to reach absolute zero, and surpass it, will a black hole appear (or a large implosion)? Or does time slow down around the absolute zero?

Here's the connection: If atoms begin to spin in its place rapidly, if we continue to starve the atom of energy (continue to push to absolute zero), then the atom will spin faster and faster; eventually to the point where the angular velocity approaches light speed, where the time slows down to prevent it from going further. Also, if we suddenly stop the effort to starve the energy, and according the the Laws of Thermodynamics, energy will rush into the point of "absolute zero" to maintain average temperature (high to low energy), therby creating an implosion or a freeze bomb.

This is really primitive, but I just want people's comments on it. Realize that I'm only a high school student who has Physics B and AP Chem on his belt, not a major or minor of any kind.

 

[DaveC426913]

Uncertainty Principle forbids particles such as atoms from reaching absolute zero. If a particle were to somehow do so, its momentum would be zero and we would still know its position. Can't happen.

So, what happens is the particles start smearing out into each otoer; they lose their individuality. Look up Bose-Einstein Condensate.

he told me that the vibrations will stop, but the atoms will continue to rotate to prevent itself from reaching zero (kind of like light speed, space slows down so that you don't pass it).

This is nonsense. Your chemistry teacher is confused.

 

[atyy]

At absolute zero, a system will be in its ground state. This is a quantum mechanical state, so if the system has eg. definite momentum, it will not have definite position, ie if you have many identical systems all at absolute zero, when you measure each system's momentum, you will find that all the systems have the same momentum; but if you measure their position, you will find each system has a different position.

A black hole does not necessarily appear at absolute zero, ie. there are absolute zero states that do not have black holes.

There is some connection between black holes in thermodynamics. Although the link between black holes and thermodynamics was postulated by Bekenstein for classical black holes, Hawking showed that this connection requires quantum mechanics, since classical black holes are all at absolute zero. http://arxiv.org/abs/gr-qc/9912119 gives the postulated laws of black hole thermodynamics, and discusses the validity of one form of the third law on p9. A different form of the third law is given on p24 of http://terpconnect.umd.edu/~jacobson/BHTlectures/lectures.ps. The full relationship between black holes, quantum mechanics and thermodynamics remains a puzzle till today http://arxiv.org/abs/0803.2030 .

 

[JesseM]

So, what happens is the particles start smearing out into each otoer; they lose their individuality. Look up Bose-Einstein Condensate.

Does this comment only apply to bosons, or is there some sense in which fermions lose their individuality?

 

[DaveC426913]

Does this comment only apply to bosons, or is there some sense in which fermions lose their individuality?

Yes. They do this with gases, such as Rubidium.

 

[JesseM]

Yes. They do this with gases, such as Rubidium.

Well, composite bound systems made up of fermions can themselves be considered bosons (see here), and rubidium atoms are "bosons" in this sense (they obey Bose-Einstein statistics). I don't think atoms obeying Fermi-Dirac statistics would lose their individuality in any meaningful sense, no matter how low the temperature.

 

[Vanadium 50]

Absolute zero is not a condition of zero motion; it is a condition of minimum motion. It is a limit because you can't get below the minimum, by definition.

Your chemistry teacher is confused.

Empty space is neither very cold nor very hot - truly empty space has no temperature. The space between, say, the Earth and the moon, isn't completely empty, but it doesn't have a temperature either, as it is not in thermal equilibrium.

It's not so clear what this has to do with special relativity, but the transformation properties of temperature in SR are somewhat controversial. Classically, there are several equivalent ways one can define temperature, and it doesn't matter which one you pick because they are equivalent. In SR, this is no longer the case.

 

[magic_claw93]

But my question is, what if we were to INFINITELY approach absolute zero?
Also, I didn't mention the fact that my Chemistry teacher initially said it was impossible to reach absolute zero (hence THEORETICALLY in my statement).
If we INFINITELY approach the speed of light (this is different from going CLOSE to light speed), time will cease to exist (due to special), and Energy will reach undefined (according to the actual E=mc^2).
Obviously, none of these would be possible with current technology, but I'm thinking THEORETICALLY again.
What I mean by black hole is that if we push an atom to the point of minimum energy (or motion, whatever you want to call it) INFINITELY, then eventually, a singularity will form due to the absence of energy at a point (energy rushes from high to low; in this case, the energy (or motion) will flood to the point of no energy).
Let me emphasize this again, I AM A HIGH SCHOOL STUDENT; when I started reading things about fermions, I was totally dumbfounded (meaning explanation might be helpful rather than just providing links to things I can't understand even more).

 

[DaveC426913]

But my question is, what if we were to INFINITELY approach absolute zero?
Also, I didn't mention the fact that my Chemistry teacher initially said it was impossible to reach absolute zero (hence THEORETICALLY in my statement).
If we INFINITELY approach the speed of light (this is different from going CLOSE to light speed), time will cease to exist (due to special), and Energy will reach undefined (according to the actual E=mc^2).
Obviously, none of these would be possible with current technology, but I'm thinking THEORETICALLY again.
What I mean by black hole is that if we push an atom to the point of minimum energy (or motion, whatever you want to call it) INFINITELY, then eventually, a singularity will form due to the absence of energy at a point (energy rushes from high to low; in this case, the energy (or motion) will flood to the point of no energy).
Let me emphasize this again, I AM A HIGH SCHOOL STUDENT; when I started reading things about fermions, I was totally dumbfounded (meaning explanation might be helpful rather than just providing links to things I can't understand even more).

You're using the word infinitely without meaning.
And you're asking 'what if we could do things we can't do?'

 

[magic_claw93]

There are lots of things we can't do that we theorize.
Special relativity is one. No way can we test that out...

 

[DaveC426913]

There are lots of things we can't do that we theorize.
Special relativity is one. No way can we test that out...

It is one of the most tested theories in all of science history. And has passed with flying colours every single time.

It is an common part of our mundane lives. You test it every time you turn on a GPS device.

 

[magic_claw93]

So do black holes surpass our concept of what is possible?

 

[DaveC426913]

So do black holes surpass our concept of what is possible?

How so?

 

[magic_claw93]

Black hole = past speed of light, absolute zero, possibly link to 4th dimension, wormholes

If black holes do exist, why can't my theory POSSIBLY happen? I'm thinking like Calculus where we lim as x->infinity.

 

[DaveC426913]

Black hole = past speed of light, absolute zero, possibly link to 4th dimension, wormholes

What do any of these things have to do with each other?

I should point out that one of them is wrong. Black holes do just fine without exceeding the speed of light.

If black holes do exist, why can't my theory POSSIBLY happen?

What you are saying is not a theory; you are merely playing with words.

 

[magic_claw93]

My HYPOTHESIS is as we merely approach the boundaries of black holes. That's why as we infinitely APPROACH absolute zero (not below it), we begin to see similarities between black holes and temperature. Same with speed, if we infinitely APPROACH speed of light, then time will cease to exist, another shocking similarity to black holes. We are approaching something tangible, not intangible.
I'm just wondering if somebody will verify to me that black hole is the LIMIT of our 3 dimensional world.

 

[DaveC426913]

Sure. Yes. Limits and asymptotes are a very common form of geometry.

But you can't use the similarity in reverse. Firetrucks and apples are both red, but that doesn't mean you eat a firetruck or drive an apple.

 

[magic_claw93]

I should point out that one of them is wrong. Black holes do just fine without exceeding the speed of light.

If it does not exceed speed of light, than how come light is SUCKED into the hole (black, not light hole). If black hole IS the speed of light, light will merely enter it and just stand still in time.

 

[magic_claw93]

So now you're stating that black holes are unrelated to speed and temperature; they are faulty comparisons, yes?

 

[DaveC426913]

If it does not exceed speed of light, than how come light is SUCKED into the hole (black, not light hole). If black hole IS the speed of light, light will merely enter it and just stand still in time.

Light does not get sucked into a black hole. Light that falls into a black hole gets infinitely red-shifted as it climbs out again.

So now you're stating that black holes are unrelated to speed and temperature; they are faulty comparisons, yes?

That depends on what comparison you're making; you haven't really made one yet, other than to show that they tend to involve mathemetical limits.

 

[magic_claw93]

Mathematical limits are not sufficient? Relativity is based on limits; all the experiments with time dilation, etc. were the foundation of limits (what happens close to speed of light?).
And also, light is being red-shifted BECAUSE its moving away from us, is it not?

 

[DaveC426913]

Mathematical limits are not sufficient? Relativity is based on limits; all the experiments with time dilation, etc. were the foundation of limits (what happens close to speed of light?).

Like I said, firetrucks and apples are both red. But red is a trivial property, shared by countless things. Not sufficient to draw other comparisons between firetrucks and apples.

And also, light is being red-shifted BECAUSE its moving away from us, is it not?

No. It is being red-shifted because it is climibng out of a gravity well.

 

[Vanadium 50]

This may be a good idea to remind people of PF's rules on overly speculative posts.

 

[magic_claw93]

If it is coming OUT of the black hole, then wouldn't it blue-shift? Doppler effect says things moving away are red-shifted, and things moving towards are blue-shifted.
Also, does that mean black hole is slower than speed of light?

 

[magic_claw93]

This may be a good idea to remind people of PF's rules on overly speculative posts.

I'm not speculating, I'm asking. I guess there's a fine line between the two...
I'm not saying that something definitely will happen (and something specific to it), I'm asking whether if something will happen.
And we're abiding by the fact that my possible "theories" are totally not unfounded, linking to "crackpottery sites".

 

[DaveC426913]

I'm not speculating, I'm asking. I guess there's a fine line between the two...
I'm not saying that something definitely will happen (and something specific to it), I'm asking whether if something will happen.

The answer is no.

Limits describe geometry; they do not dictate. Just like a colour describes a firetruck and an apple, but does not constrain their behaviour.

 

[magic_claw93]

Ok, so ideally in the future, when technology is far more advanced than we can imagine, we manage to somehow replicate the conditions of absolute zero; however, nothing will happen. The world will keep spinning, the kids are playing outside, and the sun is shining. Also, the science labs are going to just sit there and ponder about why the heck they spent so much tax money on this project.
Fine, but care to explain why nothing will happen?

 

[DaveC426913]

Ok, so ideally in the future, when technology is far more advanced than we can imagine, we manage to somehow replicate the conditions of absolute zero; however, nothing will happen. The world will keep spinning, the kids are playing outside, and the sun is shining. Also, the science labs are going to just sit there and ponder about why the heck they spent so much tax money on this project.
Fine, but care to explain why nothing will happen?

The question you have just asked is:

Why, when something happens that cannot happen, will nothing happen?

 

[yuiop]

Empty space is neither very cold nor very hot - truly empty space has no temperature. The space between, say, the Earth and the moon, isn't completely empty, but it doesn't have a temperature either, as it is not in thermal equilibrium.

Hmmm, I wonder why you require an object to be in thermal equilibrium in order to have a temperature? For example a red hot poker in air at room temperature is not in thermal equilibrium with the air and yet we can say the poker has a temperature of 800 degrees C. Are you saying that all components of the poker must be in thermal equilibrium in order to define a temperature for the poker? On a nit picking scale this is correct, but we can define an average temperature for a small given part of the poker can we not?

Now if we have a medium, say water or air and place a thermometer in the medium, the thermometer will eventually come to thermal equilibrium with the medium and this equilibrium temperature is the temperature of the medium (with a minuscule error due to warming or cooling of the medium due to the initial temperature of the thermometer). In other words one definition of temperature is that which an ideal thermometer measures just as time is what an ideal clock measures). Now if we place a thermometer in empty space far from any stars the measured temperature of the vacuum medium is the same as the cosmic microwave background temperature. Another way of looking at this is to define the temperature of a given volume in terms of the radiation emitted from the surface of the volume. Imagine a cube of vacuum. In a given time interval a certain amount of background radiation crosses the surface of the cube into the volume. In the same time interval the same amount of radiation is passing through and exiting the volume, so the cube of vacuum is effectively radiating energy (at the same rate as it absorbing energy). Since the cube of vacuum is radiating energy at the same rate as it absorbing energy from its surroundings it is thermal equilibrium with its surrounds and because it is radiating it has a temperature which equal to the background microwave energy.

So in our current universe, the average temperature of the space vacuum is not zero. If the universe continues to expand the CMBR temperature should continue to fall and given enough time should approach absolute zero. Over such extreme time scales all stars will eventually use up their thermonuclear fuel and collapse to neutron stars and sometimes to black holes. After further time black holes will have absorbed all the available material in the accretion zones but there will remain planets and dead stars that are in stable orbits about the black holes that do not end up being "consumed". At these very low temperatures, even very large black holes like the one at the centre of our Galaxy will evaporate due to Hawking radiation because they lose energy at a greater rate than they gain energy from the background radiation. At this time almost all the energy radiated by stars over the entire lifespan of the universe will be in the form of photons traversing space as will all the energy that was formally locked up in black holes. This radiation will effectively become part of the background radiation and will probably reduce the rate at which the background radiation temperature cools, but ultimately it will be a loosing battle if the universe continues to expand. The universe is going into heat death and everything is almost in thermal equilibrium with everything else, but not everything stops. The dead planets and stars in our Galaxy will continue to orbit the place where the massive black hole at the centre used to be. There will be small changes in the orbits but the mass of the central black hole is fairly insignificant compared to the mass of the whole galaxy. Some stars that have been flung out of galaxies due to near collisions with black holes etc will continue to traverse intergalactic space whether the star is dead or not and even if the universe is near heat death. If these ejected stars collide with other bodies they may generate heat and bring about further random motion of other bodies, but the effect is small and the increasing vastness of expanding intergalactic space will make these collisions very rare. Nevertheless, a very cold universe in perfect thermal equilibrium will still have motion. So what next? Will the universe become "radiation dominated" and will this have any influence on the continued expansion of the universe? Roger Penrose has some interesting ideas in his "Emperor's new mind" book about how the relationship between gravity and entropy may bring about a big crunch making the universe start all over again, but at the moment that is just idle speculation.

 

[Vanadium 50]

Hmmm, I wonder why you require an object to be in thermal equilibrium in order to have a temperature? For example a red hot poker in air at room temperature is not in thermal equilibrium with the air and yet we can say the poker has a temperature of 800 degrees C.

The poker is in thermal equilibrium with itself, and has a temperature. If you asked what the temperature of the room+poker system is, it would not have a temperature.

 

[magic_claw93]

I'm guessing you don't believe in the fourth dimension either then. Fourth dimension is something that cannot be comprehended in our 3 dimensional universe. What you're stating is the blatant fact that without evidence you refuse to imagine further than that. As a much older person (I presume) that way might have worked, but I'm wondering what if something "impossible" happens. Black holes are the perfect example. There is no evidence as to its properties. Why? Black holes are not observable. In fact, black holes are the only comprehension to giant holes in spacetime; nothing more than that proves the existence of black holes. If you believe in the fourth dimensiton and black holes, care to at least wonder what will happen? Well, this post is pretty much tired itself out so you don't have to answer my question. I just wanted to "vent" my spontaneous question as to what will happen at absolute zero (slight infringement of forum rules, but please let slip by!).