Absolute zero is often thought to be the coldest temperature possible. But now researchers show they can achieve even lower temperatures for a strange realm of "negative temperatures."

Oddly, another way to look at these negative temperatures is to consider them hotter than infinity, researchers added.

To comprehend the negative temperatures scientists have now devised, one might think of temperature as existing on a scale that is actually a loop, not linear. Positive temperatures make up one part of the loop, while negative temperatures make up the other part. When temperatures go either below zero or above infinity on the positive region of this scale, they end up in negative territory. (...)

At absolute zero, atoms would occupy the lowest energy state. At an infinite temperature, atoms would occupy all energy states. Negative temperatures then are the opposite of positive temperatures — atoms more likely occupy high-energy states than low-energy states.

"The inverted Boltzmann distribution is the hallmark of negative absolute temperature, and this is what we have achieved," said researcher Ulrich Schneider, a physicist at the University of Munich in Germany. "Yet the gas is not colder than zero kelvin, but hotter. It is even hotter than at any positive temperature — the temperature scale simply does not end at infinity, but jumps to negative values instead."

the temperature scale simply does not end at infinity, but jumps to negative values instead."

Makes perfect sense.

..woah!, interesting Vosdel..thanks..

you quoted:

..this has been suggested by serious cosmologists for 'space' of the universe,
under the concepts 'Circular Scale', and 'curvature of the space/time brane'
i.e. keep going long enough and you come back to where you started..!

circular scale has also been suggested for all 'scale', i.e. get small enough and arrive at the big picture..
.

http://www.nature.com/news/quantum-gas-goes-below-absolute-zero-1.12146

Another article, more clear and informed imo.

Technically, you read off the temperature of a system from a graph that plots the probabilities of its particles being found with certain energies. Normally, most particles have average or near-average energies, with only a few particles zipping around at higher energies. In theory, if the situation is reversed, with more particles having higher, rather than lower, energies, the plot would flip over and the sign of the temperature would change from a positive to a negative absolute temperature.

I just watched a lecture by Lawrence Krauss explaining how cosmologists fund a way to measure and have confirmed the universe is flat!

Haha, feels like history repeating itself first the earth was flat, then it was round. Now its the universe! Cant help but to see similarities hehe