5 replies to this topic

[StanleyAlexander]

SCIENTISTS ACHIEVE NEGATIVE TEMPERATURE

 

 

 

Negative temperatures could be used to create heat engines — engines that convert heat energy to mechanical work, such as combustion engines — that are more than 100-percent efficient, something seemingly impossible. Such engines would essentially not only absorb energy from hotter substances, but also colder ones. As such, the work the engine performed could be larger than the energy taken from the hotter substance alone.

Read more: http://www.foxnews.c.../#ixzz2H8kulOxC

 

From the verge:

 

http://www.theverge....te-zero-barrier

Edited by StanleyAlexander, 05 January 2013 - 11:08 PM.

[MarcZ]

Weird. 

[EVanimations]

Weird indeed. It almost sounds like something that could never be done, like cold fusion... but scientists did it, apparently. I'm guessing the explanation for this has something to do with antimatter.

 

I was about to point out that FOX Noise isn't actually news, but then I saw you posted another link. So good on you, I guess.

[SG-1]

Yeah I think I figured it out.

 

They say that in positive temperatures - hotter values expel energy out into colder ones.  Duh, leave a bowl of hot soup in the cold air and they reach equilibrium because the soup's heat escapes into the environment.

 

So you have negative temperatures - which always expel energy into positive values.  So they will always loose energy when around any temperature above absolute zero, all the way into infinity.  This does not mean it is any hotter than positive temperatures, it just means they loose energy.

 

The experiment limited the amount of potential energy, and restricted the amount of kinetic energy of the atoms using lasers.  So they changed something with the atoms to make them attract to each other.  This SOMEHOW changes the way energy is expelled.

 

So yeah, I won't pretend to know it, but I understand it.  I guess it is the anti-particle equivalent to temperatures.

 

That loop analogy..SUCKED.  Think of a number line, -10, -5, 0, 5, 10.  There still is nothing colder than 0 because the negatives just explain how energy moves in the system.  You can't have a negative speed or a temperature above infinity - both are paradoxes.

 

 

I hope I got that right.

[FutureLover1999]

Quantum statistical anomaly. Calling it negative temperature is just unnecessarily misleading. And the article is terrible, makes some truly ridiculous conclusions with no evidence.

[Craven]

http://www.scienceda...30104143516.htm - there's nice explanaiton here. Still seems kina like cheating not actually going below absolute zero but it's an interesting concept anyway.