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## Two crystalline solids at absolute zero (0 Kelvin) can create perpetual motion machine?

Perpetual motion machine: Motion that continues indefinitely without any external source of energy; impossible in practice because of friction.

The lowest recorded temperature, -273.15 degrees Celsius, is known as absolute zero. It is said (not proven) that atoms cease to oscillate at this temperature. It is the temperature at which all motion stops at the atomic level. Meaning, no atomic motion = no energy released = no heat = no entropy = no disorder. SAY you have an environment in which you can create a crystalline solid shaped in a U at absolute zero. You then place a smaller piece, also at absolute zero, on the inside edge of the U and let go. There is no heat given off between either piece, so there is no friction. No external factors.

Perpetual motion machine? Although its not much of a machine.

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• #### Thomas Reddy

• 0
May 31 2012: Interesting thought experiment.

1) It is the common belief of scientists "in the know" that absolute zero is an unattainable state. So, I don't know that your system is possible.

2) I'm a little out of my depth here, but if we were to hypothetically reach absolute zero, then I believe that the system would fall into a bose-einstein condensate.

3) Assuming you could construct the system you're describing, the very motion of the oscillation would create a transfer of kinetic energy between the two objects. Some of that energy would translate into an increase of heat. As the two atoms come near each other, the electromagnetic fields of the orbiting electrons will interact with one another, and there will be some non-zero energy transfer.

I believe I'm fairly accurate on all of these points, but if there are any physicists on here who have a greater knowledge about physics surrounding absolute zero, please chime in.

There was a good video which I had seen a while ago on PBS about absolute zero that you may want to watch if you're interested:
• #### Michael Alexander

• 0
May 31 2012: I understand the actuality of this experiment taking place and/or being correct is a small percentage. Theoretically, I thought there was a chance it may work so I had posted it. I am only a 19 year old college student studying biology so I most certainly am no physicist. Therefore, my knowledge of science has only begun. All of your points seem correct to me as well, thanks for the video!
• #### Thomas Reddy

• +1
May 31 2012: Intellectual curiosity is healthy. It's those questions which lead to scientific or engineering advancements, or alternatively giant mega corporations with spectacularly underperforming IPO's.

The real problem of the experiment, assuming you can get all of the I urial conditions worked out is that the actual movement of all the parts would generate heat energy. You have to account for all sorts of weird interactions that you normally ignore because they are usually so insignificant. But all of those interactions would bring you above absolute zero.

Quantum mechanics also starts to take control in these sorts of environments, so the concept of zero atomic movement becomes a real problem. Exause of heisenbergs uncertainty principle.

When you need to take multiple advanced physics classes to prove you wrong, you've asked an interesting question :)

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