Probably lazy of me to ask here - but what happens to matter/energy at absolute zero?

Replies to This Discussion

Permalink Reply by Jaume on January 11, 2010 at 2:49pm

Molecular motion never fully ceases near absolute zero, although it slows enough to make heat transfer impossible. You can't cool matter down to absolute zero (it would ultimately means removing that matter from the universe.) And even if you could, its energy wouldn't be zero: it would still have the energy of the ground state.

Permalink Reply by Howard S. Dunn on January 11, 2010 at 4:11pm

Thanks.

Permalink Reply by Howard S. Dunn on January 11, 2010 at 4:35pm

BTW - what are your thoughts re: once all matter and energy reach a state of homogeneous diffusion - perfect equilibrium - and an even temperature - near, I guess, absolute zero; will the complete lack of any contrast render the difference between everything and nothing moot?

I ask because there is all kinds of discussion about the 'nothing - before the big bang' - but I hear little about the total loss of information that may happen at a distant-future end-position of space|time.

Obviously, there may be a bang|crunch cycle. But if space|time is flat - won't it be 'from nothing we have come and to nothing we return?' (given that I am only being silly with the mystical language.) What I mean is, without contrast, information is - well - not legible at best and nonexistent at worst. And the end-position predicted by the Third Law suggests, to me, a universe that entirely lacks contrast of any sort.

Permalink Reply by Jaume on January 12, 2010 at 3:32am

You'll still have some contrast between the macroscopic and microscopic levels. And a lot of information such as particles properties (momentum, spin, mass, etc.), which actually represents most of the total information in the universe, is not likely to disappear as entropy increases, even if the universe becomes a baryonic soup.

By the way, I had never thought about it in these terms before, but the fact that absolute zero represents a state of minimal entropy might be a sufficient reason to prevent the universe to expand and cool down infinitely.

Permalink Reply by Howard S. Dunn on January 12, 2010 at 9:47am

Interesting. I had never come close to thinking about that - well, maybe in a peripheral, poetic way as I tend to.

This appears to go to an inquiry I have always been nagged by: the strange quality of entropy's lack of a true counterpart.

For example - the uninitiated might consider that the most violent forms of entropy are explosions. Makes sense - things fall apart ... very fast. But stars are constantly exploding and, yet, hydrogen becomes more complex - not less - in the heart of that explosion - forming into helium and the basic building blocks of carbon based life forms. Then, strangely, it is the most violent explosions that generate the majority of the elements - super novae or, even, the Big Bang itself.

There does appear to be some version of some principle or attribute of reality that tends to work the opposite way that entropy does. Harmony? that seems a poetic word - though it can be described in physical terms - sympathetic waves, harmonics, etc.

Nevertheless, pure white light is little different than total darkness in terms of contrast or discernibility. And I think that a baryonic soup might qualify as distinct from nothing - but not much different.

Permalink Reply by Jaume on January 12, 2010 at 10:51am

This appears to go to an inquiry I have always been nagged by: the strange quality of entropy's lack of a true counterpart.

Actually there's one, albeit transient, and it can't be applied to closed systems. Poetically, you could call it 'life' or even 'harmony' (although it'd be a rather chaotic kind of harmony.)

And Re stars: while it's true that the entropy of a closed system never decreases, entropy within parts of this system is governed by the laws of probability and may either decrease or increase. Otherwise elements heavier than iron (the most stable of all elements) could never form.

Permalink Reply by Lee on January 11, 2010 at 8:13pm

As Jaume said, you will never have absolutely no motion, even if you managed to get to absolute zero, because the ground state has some energy. An alternative way to think about it is can think about Heisenberg's uncertainty principle, if you are absolutely sure of the particle's momentum you become less sure of its position, and if you are unsure of its position it is like a the particle has molecular motion.

Not very versed with cosmology, but I think you refer to the second law of thermodynamics. This depends on how fast the universe is expanding. If the universe is expanding faster than it increases in entropy that scenario will not come to pass.

Permalink Reply by Howard S. Dunn on January 11, 2010 at 10:37pm

Yeah - maybe the second - thought it was the third - that basically, matter and energy's tendency to 'find equilibrium' will finally result in all matter being evenly diffuse and all energy being equally distributed - or some such. It seems to me that, at that point, the lack of contrast will make all measurements moot - if you see what I mean.

Permalink Reply by Mike Harvison on January 11, 2010 at 10:39pm

This link provides a good jumping off place on the topic of universal expansion and the fluctuations of the vacuum:

http://apod.nasa.gov/apod/ap100103.html

Permalink Reply by Howard S. Dunn on January 12, 2010 at 9:00am

Thanks. You know, I have a more poetic/philosophical/artistic approach to 'nothing' that I have been working on for over thirty years now. Weirdly, I only recently have become aware of the dark matter inquiry (last few years or so) - also, Glenn Sogge pointed me to Lawrence Krauss only very recently.

What I have long wondered about was the role of 'nothing' - which can be described as the massless, energy free areas of the universe responsible for 'darkness', 'cold', 'emptiness', 'vacuum', etc. This is an extrapolation of the artistic principle of chiaroscuro. That is to say, without contrast, there can be no discernible image.This becomes a substance/non-substance duality that has nothing (pardon the pun) to do with 'spirits', 'ghosts', or any other mumbo jumbo. The universe appears to be quite full of nothing.

The question I have had is whether nothing - which appears to be everywhere (though 'in flux' , since things - energy and matter - move within/with it) has a volume, if not a density (since it has no mass). It seems that, without matter/energy, nothing would collapse down to, well, nothing. But it seems equally true that matter and energy, without the 'medium' of nothing to exist in, would also collapse down to 'nothing' (or some kind of infinite mass) as well. Then it occurred to me that if matter/energy is a manifestation of mass - then nothing is a manifestation of volume in that it requires both matter/energy and empty space to arrive at the property of 'density'.

I know. I don't have the math. But it is odd that I arrived at an uncannily similar view of the cosmos to that of those pursuing the 'dark energy' hypothesis without having the math.

Permalink Reply by thewoodenwand on February 19, 2012 at 11:40am

Unfortunately you are all thinking in trems of millions and only billions of years. New deep penetrating telescopes looking back over 13 billion years have found the standard model is not as absolute as we expected. This means the Big Bang could have been an event that created the rules of our universe not just the mass. This also means mass, speed of light, gravitational constant and many things are slowly changing, Time itself may cease may exist  18548711699200000000000000000000000000000000 years from now (inverse of Planck time). The expansion of space /time results in only a change in our 3 spacial dimensions, if time is expanding then time would last forever and it cannot.