h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Sorry, nice little entry BUT...

'at Absolute Zero the molecules do not vibrate at all'

Wrong - not true blah blah - surprised this wasn't picked up in Peer Review

Anyone who is a physicist or chemist would be able to tell you that all energy is quantised - this includes vibrational and rotational degrees of freedom. With both there is a lowest possible level - this is non-zero and is what is occupied at absolute zero. This is called the zero-point energy and so molecules in fact DO vibrate at absolute zero.

Er.. not quite, the problem is the Heisenberg Uncertainty Principle. One can never be certain about how much energy something has if the energy concerned is very small. This minimum is called the zero point energy.

It also explains why thete is no such thing as a total vacuum.

I happen to be a low temperature physicist so have found the conversation quite interesting.

Er... yes, I don't care just how much we can be sure about, things DO vibrate at absolute zero. End of...

Heisenberg has nothing to do with it.

interesting

what is the lowest temp. that you have achieved??

i remember from O level physics that 0 kelvin was the point you get when you project back the graphs from the pressure laws and its the theoretical point where gasses have zero temp. volume and pressure

keep up the good work

and stay cool

cheers

taff
agent of kaos

Sorry, it does appear that Heisenberg has a lot to do with it. My apologies for that comment.

http://www.answers.com/topic/zero-point-energy
http://en.wikipedia.org/wiki/Zero-point_energy

I thought in my haste last night that you were referring to my post when you said not quite. It may be you were rather agreeing with me about the innacuracy of the article? Although I'm still not sure about that though. Are you saying there is no such thing as zero-point energy vibration? Surely not.

I am a researcher in chemical biology and we do an awful lot of work involving kinetic isotope effects - the origin of which is (partly)down to the differences in zero-point energy vibration between C-H and C-D bonds. In fact theory of vibrational motion come into an awful lot of chemistry so please don't think I'm coming from an O level perspective. I am well past PhD level thankyou.

Last time I heard a talk on such things, I believe the lowest temperatures achieved were now in the femtoKelvin range (10^-12 K) but I may be behind the times.