General Discussion
Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region ForumsAbsolute zero temperature barrier breached by scientists with interesting implications
http://www.sciencedaily.com/releases/2013/01/130104143516.htmJan. 4, 2013 What is normal to most people in winter has so far been impossible in physics: a minus temperature. On the Celsius scale minus temperatures are only surprising in summer. On the absolute temperature scale, which is used by physicists and is also called the Kelvin scale, it is not possible to go below zero at least not in the sense of getting colder than zero kelvin.
According to the physical meaning of temperature, the temperature of a gas is determined by the chaotic movement of its particles the colder the gas, the slower the particles. At zero kelvin (minus 273 degrees Celsius) the particles stop moving and all disorder disappears. Thus, nothing can be colder than absolute zero on the Kelvin scale. Physicists at the Ludwig-Maximilians University Munich and the Max Planck Institute of Quantum Optics in Garching have now created an atomic gas in the laboratory that nonetheless has negative Kelvin values. These negative absolute temperatures have several apparently absurd consequences: although the atoms in the gas attract each other and give rise to a negative pressure, the gas does not collapse a behaviour that is also postulated for dark energy in cosmology. Supposedly impossible heat engines such as a combustion engine with a thermodynamic efficiency of over 100% can also be realised with the help of negative absolute temperatures.
In order to bring water to the boil, energy needs to be added. As the water heats up, the water molecules increase their kinetic energy over time and move faster and faster on average. Yet, the individual molecules possess different kinetic energies from very slow to very fast. Low-energy states are more likely than high-energy states, i.e. only a few particles move really fast. In physics, this distribution is called the Boltzmann distribution. Physicists working with Ulrich Schneider and Immanuel Bloch have now realised a gas in which this distribution is precisely inverted: many particles possess high energies and only a few have low energies. This inversion of the energy distribution means that the particles have assumed a negative absolute temperature.
dipsydoodle
(42,239 posts)No pun intended.
AngryAmish
(25,704 posts)bravo
dipsydoodle
(42,239 posts).
Ikonoklast
(23,973 posts)The next century will be interesting, once we break our shackles to last century thinking.
Recursion
(56,582 posts)...since a Boltzmann crystal at 0K has 0 entropy. If it could have negative entropy, then we have a true information sink.
Fumesucker
(45,851 posts)Xipe Totec
(43,872 posts)kentauros
(29,414 posts)And the proper thinking of improbability added
TheMadMonk
(6,187 posts)kentauros
(29,414 posts)I only knew that "fairy cake" was used somewhere in it.
What is fairy cake, anyway?
JoeyT
(6,785 posts)I looked it up right after I read that book.
kentauros
(29,414 posts)like "biscuits" for cookies.
I wonder what they think of the "fairy cake" craze in the states right now...?
TheKentuckian
(24,934 posts)Victor_c3
(3,557 posts)This can't be a good thing. When god created us 6,000 years ago I don't think he intended us to do this.
Look out for the next super-storm or sinkhole. There'll be divine retribution for this - I'm sure.
(I hope you guys can pick up on my sarcasm)
Saboburns
(2,807 posts)Temperature is a measure of kinetic energy, at absolute zero there zero kinetic energy.
But, how can something have negative kinetic energy??
I don't get it.
Recursion
(56,582 posts)Since they instead occupy a range of states among several probability distributions, you can get weird stuff like that (from the article, you get negative absolute temperature by, oddly enough, superheating gas).
Sirveri
(4,517 posts)So it's possible... I guess. If you hit the 'I believe' button.
Make7
(8,543 posts)It was two parts, so it's about an hour and forty five minutes. There is a long history on the quest of scientists to reach lower and lower temperatures - it becomes really interesting when they get to temperatures where the normal properties of matter break down and weird things start to happen.
The full program is on YouTube:
http://www.youtube.com/watch?v=y2jSv8PDDwA
Or if you want to skip ahead to where I think it starts to get really interesting:
http://www.youtube.com/watch?v=y2jSv8PDDwA#t=4458s