Beyond 'absolute zero' temperatures get hotter
I'll let Kurt explain.
Absolute zero is not absolute

 Forum God/Goddess
 Posts: 22670
 Joined: Wed Sep 04, 2002 8:57 pm
 Location: Name sez it all
 Contact:
Re: Absolute zero is not absolute
I did a paper on a similar phenomenon back in undergrad. I think it was for my statistical mechanics/thermodynamics course.
It uses one of the thermodynamic definitions for temperature, which is the inverse of the rate of change of entropy versus the internal energy of the system (with some other things being held constant). When I did my paper on it, the systems that they said had "negative absolute temperature" were, as I recall, gases that were very hot in the conventional sense of temperaturethey had loads and loads of internal energy.
This works off of a definition of entropy having to do with disorder in the system, which really isn't a great way to define entropy. it all gets rather circularentropy gets defined in terms of energy states (which is one measure of temperature) and temperature gets defined in terms of entropy and energy.
It's kind of a mathematical sleightofhand to say that is negative absolute temperature, since as the article makes clear, the atoms still have a variety of energies.
It uses one of the thermodynamic definitions for temperature, which is the inverse of the rate of change of entropy versus the internal energy of the system (with some other things being held constant). When I did my paper on it, the systems that they said had "negative absolute temperature" were, as I recall, gases that were very hot in the conventional sense of temperaturethey had loads and loads of internal energy.
This works off of a definition of entropy having to do with disorder in the system, which really isn't a great way to define entropy. it all gets rather circularentropy gets defined in terms of energy states (which is one measure of temperature) and temperature gets defined in terms of entropy and energy.
It's kind of a mathematical sleightofhand to say that is negative absolute temperature, since as the article makes clear, the atoms still have a variety of energies.
Re: Absolute zero is not absolute
It's kind of a mathematical sleightofhand to say that is negative absolute temperature, since as the article makes clear, the atoms still have a variety of energies.
Or maybe something is getting lost in translation. An artifact of the math and translation to English.

 Forum God/Goddess
 Posts: 1969
 Joined: Wed Apr 04, 2012 8:36 pm
 Location: Wisconsin
Re: Absolute zero is not absolute
Sandi wrote:It's kind of a mathematical sleightofhand to say that is negative absolute temperature, since as the article makes clear, the atoms still have a variety of energies.
Or maybe something is getting lost in translation. An artifact of the math and translation to English.
I think you are right. I think NS does a nice job of reporting on this.
http://www.newscientist.com/article/dn2 ... zero.html
Re: Absolute zero is not absolute
Henry Vilas wrote:I'll let Kurt explain.
No prob. Ever spent a winter in the U.P.?
It gets colder and colder until absolute zero. Then after a while you start feeling warmer. Then, pretty soon, you're dead.
Actually, I thought this quote, from the New Scientist article was great:
"The temperature scale as we know it starts at zero and goes up to infinity, but it doesn't stop there," says Ulrich Schneider of the Ludwig Maximilian University of Munich in Germany.
To Infinity ... and Beyond!
Re: Absolute zero is not absolute
kurt_w wrote:Actually, I thought this quote, from the New Scientist article was great:"The temperature scale as we know it starts at zero and goes up to infinity, but it doesn't stop there," says Ulrich Schneider of the Ludwig Maximilian University of Munich in Germany.
To Infinity ... and Beyond!
Yeah it is rather hard to wrap your mind around "beyond infinity."
Perhaps it is a result of their math: like π ( PI ) which cannot be completely defined as a decimal because the decimal representation never ends. However we know that PI does have a finite value, it's just that our math is inadequate to express it.

 Forum God/Goddess
 Posts: 3082
 Joined: Wed Jul 20, 2005 3:33 pm
 Location: Memorial Union
 Contact:
Re: Absolute zero is not absolute
Sandi wrote:Perhaps it is a result of their math: like π ( PI ) which cannot be completely defined as a decimal because the decimal representation never ends. However we know that PI does have a finite value, it's just that our math is inadequate to express it.
Not at all. Pi is an irrational number that is a constant. Infinity is a concept that can't be used in algebraic equations like pi can.
Back one tangent, I'd comment that the history of how we measure temperature is a rather interesting one. And Celsius, Fahrenheit and Kelvin are only three of many (mostly archaic) scales. Check these out: http://en.wikipedia.org/wiki/Comparison ... ure_scales

 Forum God/Goddess
 Posts: 1969
 Joined: Wed Apr 04, 2012 8:36 pm
 Location: Wisconsin
Re: Absolute zero is not absolute
'Laugh while you can monkey boy' /boys. The shit that makes the worldgoround today is not, nessessarily, intuitive.
MH
http://www.youtube.com/watch?v=345uegSj ... ata_player
MH
http://www.youtube.com/watch?v=345uegSj ... ata_player
Re: Absolute zero is not absolute
Mad Howler wrote:'Laugh while you can monkey boy'
http://www.youtube.com/watch?v=345uegSj ... ata_player
Here's the trailer:
http://www.youtube.com/watch?v=lOzZVGpjkLg
We've already got johnfajardohenry and jonnygothisgun. Wonder when John Whorfin, John Icicle Boy, and John Yaya will show up....
Who is online
Users browsing this forum: No registered users and 3 guests