Absolute Zero and implications

[mmg600]

I'm not a scientist, but I really enjoy reading the perspectives on these boards. I have some questions I hoping to hear a lot of perspectives on.

I know absolute zero has never been reached, but in what ways are we attempting to find absolute zero currently?

If, hypothetically, we were able to reach absolute zero, what would be the practical and theoretical implications?

Some say that time (i.e. aging) stops in absolute zero...I'm interested in hearing what people think then about absolute zero's theoretical implications for time travel. I ask because I met a physicist who was building a piece of technology he believed would reach absolute zero, and believed he would therefore be able to manipulate this towards travel through time and space. I understand that he is outside of the mainstream thought, but I want to know a little more about these ideas...

 

[zhermes]

Absolute zero cannot be reached. Just like the speed of light cannot be reached or surpassed; just like energy cannot be created or destroyed; just like the entropy of the universe cannot decrease.

It doesn't make sense to ask, therefore, what would happen at absolute zero.
It would not have anything to do with space or time-travel. From a biology perspective, aging would stop (but there would be lots of negative problems first).

 

[mmg600]

Absolute zero cannot be reached.

Are you only saying that because it has never been done?

But regardless, I am more interested in the hypothetical implications of the (unlikely) event that we can reach absolute zero...

 

[bcrowell]

It's going to be hard for anyone to comment on far-out ideas that we're only hearing described in very general terms.

 

[Shenstar]

Why are there these limits on speed, temperature, entropy not decreasing?

I mean aren't these just limited to our current understanding. What if the universe doesn't truly follow the 2nd law of thermodynamics and the arrow of time can be reversed.

Or absolute zero being reached

Photons travel at the speed of light just like other wave from the em spectrum, so it should be in the realms of possibility just that our current understanding can not perceive it

 

[zhermes]

Are you only saying that because it has never been done?
But regardless, I am more interested in the hypothetical implications of the (unlikely) event that we can reach absolute zero...

As my analogies were meant to illustrate, it is not that it has never been done---it is that it cannot be done. According to modern physics, it is not unlikely - it is impossible.

Why are there these limits on speed, temperature, entropy not decreasing? I mean aren't these just limited to our current understanding. ...

Of course. It is entirely possible that quantum mechanics (and modern extensions) are wrong, and absolute zero is indeed reachable. That is however outside the realm of science, and its pointless to speculate.

 

[twofish-quant]

One way of thinking about it is that the important number is not T, but 1/T. If you look at the thermo equations, usually the important number is not T but 1/T. So going to absolute zero is like going to infinity.

Also the weird thing is that you can't get to absolute zero, but you can get to negative temperatures or infinite temperatures. This makes a lot more sense if you think about things in terms of 1/T rather than T.

 

[nesp]

It might help to think of T as a measurement of the average kinetic energy in the system. Absolute zero would imply no kinetic energy, not even from quantum processes, which is not possible to reach thermodynamically.

 

[Ynaught?]

While absolute zero has not been reached, and may not be reachable, scientists have cooled things to incredibly low temperatures (0.0000000001 degrees above zero)http://ltl.tkk.fi/wiki/LTL/World_record_in_low_temperatures. Some cool stuff happens at extremely low temperatures like: superconductivity, superfluidity, and the formation of Bose-Einstein condensates and fermionic condensates.

 

[daveb]

As my analogies were meant to illustrate, it is not that it has never been done---it is that it cannot be done. According to modern physics, it is not unlikely - it is impossible.

That's not exactly true. The nature of science only tells about patterns we observe. If the pattern has never been observed to deviate, we call it a law. We have theories to explain why those laws are the way they are. This is what makes theories so powerful - they are explanatory, and can be revised or discarded when new (replicable) data arises that does not fit within current theory. If that data goes against a law, and can be replicated, then the law must be discarded and replaced with a new one.

In this way, nothing is impossible - it just has never been observed to deviate, and scientific knowledge is tentative. http://www.nsta.org/about/positions/natureofscience.aspx"

 

[nesp]

In this way, nothing is impossible - it just has never been observed to deviate, and scientific knowledge is tentative. http://www.nsta.org/about/positions/natureofscience.aspx"

It's more than that. If absolute zero were to be possible, it would negate quantum mechanics. So it's more than never having been observed, it also invalidates the foundations of a theory with a plethora of experimental verifications. So I suppose it's OK to say that reaching absolute zero has the same level of being possible as quantum mechanics has of being false, but no more than that.

 

[Ynaught?]

Nesp, where did you get the idea (which is incorrect) that absolute zero "would negate quantum mechanics" or "invalidate the foundations of the theory"? I suggest you read up a bit on zero-point energy.

 

[nesp]

Ynaught, in my attempt to simplify for the OP, I oversimplified and equated absolute zero as being the state at which all motion stops in a statistical thermodynamic sense, and all quantum motion stops, including that related to zero point energy. The second is what I was referring to as not possible. Concerning the first, I thought even that was theoretically impossible, is it? Thanks for the correction.

 

[Ynaught?]

Nesp, actually I think you are correct (except for the negating QM part). A classical system cannot be brought to absolute zero because of the second and third laws of thermodynamics (assuming the correctness of the first law). But, because of the HUP the zero point energy of a quantum system is not zero even if its vibrational number (0 Kelvin) is zero.

 

[Lost in Space]

Could a singularity be at absolute zero?

 

[twofish-quant]

Could a singularity be at absolute zero?

There is.

A singularity is where you divide by zero, and since the important number is 1/T, there is in fact a mathematical singularity at T=0.

 

[Lost in Space]

There is.

A singularity is where you divide by zero, and since the important number is 1/T, there is in fact a mathematical singularity at T=0.

So could this also mean that a singularity is in effect a monopole?

 

[DGB]

I apologize if this question is a bit off topic, but –

Suppose you had a macro object super-cooled to a temperature approaching Absolute Zero, and this object was then placed within a hypothetical container that would insulate the object from the outside environment, in addition to maintaining the integrity of it’s super-cooled state (that is, heat from the hypothetical container would not flow into our macro object).

Next, suppose you took the macro object and container to a big, sunny field and opened the container, exposing the environment to this super-cooled object and vice-versa. What sort of effects, if any, would the sudden introduction of this super-cooled object have on the surroundings?

My first guess – a bit dramatic, I’ll grant – is that this event would be like the thermodynamic equivalent of busting open the Hoover Dam; all of the surrounding heat would rush into try and fill the temperature gap created by the event by the super-cooled object, resulting in a rapid, explosive decrease in temperature in the immediate area, depending on the object’s mass.

Of course, I’m no scientist, so I’m sure that there’s a likely more plausible explanation out there.

Anyway, thanks for listening.

 

[Drakkith]

The object would quickly heat up by absorbing heat from the surrounding. And by quickly I mean somewhere on the order of minutes. There would be no explosive anything unless you had something like liquid oxygen boiling away inside the object but unable to get out initially. Hit up youtube for liquid nitrogen, liquid oxygen, and other supercold liquid videos.

 

[Tanelorn]

Every cooling method I have read only takes out 90% to 99.9% of the heat energy in a body. Sometimes 2, 3 or 4 methods are used simultaneously to get things even cooler in steps. If I remove 99% of the energy and then 99% of what is remaining and then do this 2 more times then we are still a million miles from 0 remaining energy and absolute zero. That is why I don't think you can achieve absolutes like this eg. speed of light etc.

 

[DGB]

cool. I've been doing a little research into supercooling and other physics topics lately, although I haven't been able to find a whole lot of documentation on a lot of these more hypothetical things, so I'm glad I've been able to get information from multiple perspectives. thanks!

 

[shifty88]

Are you only saying that because it has never been done?

But regardless, I am more interested in the hypothetical implications of the (unlikely) event that we can reach absolute zero...

The closer you get to the speed of light it becomes harder and harder to accelerate.
The same is true for temperature, the closer you come to 0 Kelvin, it becomes harder too lower the temperature further.

Maybe in the future we will know of more efficient means of reaching 0 k.
As for the practicalities of reaching 0 k, I am not sure. But as far as I know, some really interesting things happens to some elements as it cools.

Also the cooler electricity wires become resistance decreases. So that's something.
Hope this helps

 

[Mind Bender]

I have heard many bizarre theories on what happens at Absolute Zero. Some think that space-time itself becomes crystallized, making it possible to time-travel or travel faster than light! Others believe that when Absolute Zero is reached, it might cause instant and complete entropy of the Universe. But it may be a good thing that the Laws of Thermodynamics prohibit such a goal.

 

[Drakkith]

I have heard many bizarre theories on what happens at Absolute Zero. Some think that space-time itself becomes crystallized, making it possible to time-travel or travel faster than light! Others believe that when Absolute Zero is reached, it might cause instant and complete entropy of the Universe. But it may be a good thing that the Laws of Thermodynamics prohibit such a goal.

I'm pretty sure those are complete fabrications.

 

[Cosmo Novice]

I'm pretty sure those are complete fabrications.

Im also pretty sure. As sure as I am I that I didn't ride Puff the Magic dragon into work this morning!

 

[Lost in Space]

Yes, quantum theory states that there will always be a vibration of particles and they can never reach a state of non vibration (like a pendulum can never be perfectly at a rest state) because there will always be tiny fluctuations that don't allow a temperature of absolute zero to be attained. Absolute zero is a boundary that may be achievable inside a singularity but singularities are infinite and non quantisable.

 

[nucl34rgg]

A system at absolute zero would still have some zero-point energy. Absolute zero doesn't violate QM. A system at absolute zero has all of its particles in its lowest energy states, still subject to the Pauli Exclusion Principle. (Absolute zero is not a state of no vibration, but this is commonly misrepresented.) Absolute zero is unattainable practically.