Absolute Zero

[Deep_Eye]

Does anyone know the exact temperature of absolure zero? And what I was wondering is how people would even test that and know that it applies to ALL molecules(such as all different types).

[Tinaa]

It is -459 F or -273 C or 0 Kelvin.

At absolute zero, all motion stops.

[Josh]

...and she means ALL motion .. like on a subatomic level!

[Deep_Eye]

Ahh... so even quarks and neutrinos and all those others?

[Tinaa]

Remember, even in the deepest darkest outerspace, the temperature is three degrees above absolute zero. There is still enough heat from the big bang to heat the universe.

[Planetwatcher]

Sounds a lot like winter in the north central U.S. and maybe the western half of Canada. :D

[Fraser]

All matter doesn't stop moving at Absolute Zero, it's just the limit at which you can't draw any further energy from an object. The oscillations of atoms don't completely stop, even at Absolute Zero. Here in Vancouver, we have pretty mild summers. It doesn't always snow every year.

[Deep_Eye]

OK, thanks!
And, summers here usually get up to about 110 f on really hot days, and about 5 below f (without wind chill) on winter days.

[RACHRYAN]

I Dont Know How To Post A New Thread

[papageno]

Does anyone know the exact temperature of absolure zero? And what I was wondering is how people would even test that and know that it applies to ALL molecules(such as all different types).
In the old days, the absolute zero was extrapolated using different gas thermometers (http://www.shef.ac.uk/physics/teaching/phy001/unit1.html).

[GDwarf]

One wonders, is there an 'absolute heat' (Or 'absolute 100')? The temperature at which something cannot get any hotter. As far as I can tell there is no such thing, but it might be kinda neat to know about, if it existed.

[Swift]

One wonders, is there an 'absolute heat' (Or 'absolute 100')? The temperature at which something cannot get any hotter. As far as I can tell there is no such thing, but it might be kinda neat to know about, if it existed.
Somewhere on the old BABB forum we had that discussion. IIRC, the generally feeling was no, there was no upper limit, though, the temperature of the universe just after the big bang (whatever "just after" means) would probably be the hottest that has been reached.

[rahuldandekar]

Wouldn't there be a temperature where a substance just lost heat faster than it gained heat?

[ToSeek]

One wonders, is there an 'absolute heat' (Or 'absolute 100')? The temperature at which something cannot get any hotter. As far as I can tell there is no such thing, but it might be kinda neat to know about, if it existed.

See this thread. (http://www.bautforum.com/showthread.php?t=33920)

[howard2]

Absolute Zero is -273Deg Kelvin. The uncertainty principle forbids that all motion stops. Because we would then know the velocity and the position of a particle. As the late great Prof. R.P.Feynman used to say. They have to jiggle around a bit.

[eburacum45]

no, absolute zero is zero degrees Kelvin, and -273.15 Celsius, or -459.67 Farenheit.
In actual fact I am suspicious of these figures slightly, as they are accurate to only two decimal places.
It seems unlikely that the real value of absolute zero is exactly -273.15 C, unless I am missing something.

[eburacum45]

After a quick google;
all is clear...
the Celsius scale is actually defined via the Kelvin scale, so that 0 degrees Celsius is exactly 273.15 kelvin.

That makes sense...

[swansont]

Absolute Zero is -273Deg Kelvin. The uncertainty principle forbids that all motion stops. Because we would then know the velocity and the position of a particle. As the late great Prof. R.P.Feynman used to say. They have to jiggle around a bit.

As v tends to zero the wavelength gets really big, so you wouldn't know the position too well. So you wouldn't have much of a problem with the HUP. The third law of thermodynamics tells us that absolute zero is unattainable, so it's not like the two disagree.

[Paul Mitchell]

As v tends to zero the wavelength gets really big, so you wouldn't know the position too well. So you wouldn't have much of a problem with the HUP. The third law of thermodynamics tells us that absolute zero is unattainable, so it's not like the two disagree.
Fraser is also right. In a two body system such as a hydrogen molecule the wave-function includes an n+0.5 term, so even at absolute zero where n=0 some of the energy is still there.

Thinking about it, presumably this means that you cannot actually cool hydrogen to absolute zero (even if the third law allowed it) because you can't extract that last bit of (thermal) energy.