Coldest Place in the Universe

Chris Gondek writes "The Sydney Morning Herald has an article on how NASA has released a high-quality image of the coldest place found in the universe. Five thousand light years from Earth in the constellation of Centaurus, the nebula, a gas cloud formed from a dying star, has a temperature of minus 272 degrees. It is only one degree warmer than absolute zero, the coldest possible temperature, when atoms cease to vibrate and radiate no heat whatsoever. This radiation is the remnant of the Big Bang, the explosion which forged the universe in trillion-degree temperatures. More than 11 billion years later, this heat has cooled to minus 270 degrees, but is still detectable."

Comments

Damn That's Cold....

[Anonymous Coward]

Almost as cold as Hillary Rosen's heart 8^)

I thought I found that last month...

[Anonymous Coward]

You mean it's *not* my ex-girlfriend's soul?

Grumble, grumble - absolute zero

[altairmaine]

As it turns out, absolute zero is not the "coldest possible temperature". It is impossible to attain absolute zero, as a little basic quantum mechanics tells us. Particles will ALWAYS retain some amount of energy, the "Zero Point Energy", which cannot be removed. More accurately, we can say that absolute zero is the lower bound on the range of possible temperatures - but is not included.

Re:Grumble, grumble - absolute zero

[Anonymous Coward]

yes. the zero point energy is correct... but not to be a pest, atoms cannot vibrate as is suggested in the original post. only molecules may vibrate. the zero point energy comes into play for molecules because the energy, E, of a simple harmonic oscillator (simplest approximation) will be:

E = nu ( v + 1/2)

where v is the vibrational quantum number and nu is related to the force contant. nu is positive, and v is always a non-negative integer, so even when v is zero the energy is nu/2. freshman chemistry students are told that this is to accomodate the heisenberg uncertainty principle in that a particle that is not vibrating would have a definite position and momentum.

another poster hinted on what has been stated eloquenty for hundreds of years and restated by homer: in this house, we obey the laws of thermodynamics! the third law states:

"if the entropy of every element in its most stable state at T=0 is taken as zero, then every substance has a positive entropy which at T=0 may become zero, and which does become zero for all perfect crystalline substances, including compounts"

WTF? an alternate statement has more meaning in our context:

"it is impossible to reach T=0 in a finite number of steps".

thus, as altairmaine suggests, it is impossible to reach absolute zero. other posters suggested that it is only possible to cool things by contact with a colder substance. for those people i would suggest doing a google search on the term "adiabatic demagnetization". research into bose-einstein condensates work with clusters of atoms at fractions of a kelvin, and it is not because they have a super-secret stash of a zero-kelvin heat sink. :)

reference: "Physical Chemistry" by Peter Atkins. 5th ed.

Re:Grumble, grumble - absolute zero

[Tempest]

Actually, there is another method of cooling an object, you physically slow it's atomic vibration. It's been demonstrated down to at least 0.0000001 C above absolute zero (see NASA's site) using lasers and magnetic traps. Research utilizing the technique include Bose-Einstein Condensates and Superfluids.

~~~~~Chris Giorgi~~~~~

I Apologize in Advance

[dupper]

from the star-trek-episode-ideas dept.

Most frigid place in the universe? They've already shown Janeway's quarters.

Ba-dum-ch-OW! That hurt!

Re:yahoo for the big bang _THEORY_

[SomeGuyFromCA]

> Entropy and evolution can never co-exist.

Sure they can. Entropy only applies in a closed system. The earth is continually receiving energy from the sun, hence the earth is not a closed system.

Besides, who's to say God and evolution cannot coexist? What if that's the method He used?

New Project

[WoTG]

... and all of a sudden, 1000 Overclockers wonder, "How do I get my Athlon to Centaurus?"

Re:Houston we have a problem here

[Xilman]

Conclusion - unless there is some sort of active cooling, nothing can cool down to less than temperature of the background radiation (3K).

Correct.

There is active cooling in this case, and it works the same as a domestic refrigorator. Both systems cool down because gases are expanded, thereby doing work. That energy has to come from somewhere and it comes from the heat content of the gas: it cools in other words.

At the center of nebulae like these is a star which is driving off the remnants of what was previously its outer layers. That is, its atmosphere is expanding. If the heat loss through expansion is greater than the heat input from the rest of the universe, the gas will cool.

Paul