Record Temperature Set: Colder than Absolute Zero

Absolute zero is often thought to be the coldest temperature possible. But now researchers show they can achieve even lower temperatures.

January 4, 2013
3:31 AM EST
When an object is heated, its atoms can move with different levels of energy, from low to high. With positive temperatures (blue), atoms more likely occupy low-energy states than high-energy states, while the opposite is true for negative temperatures (red). CREDIT: Image courtesy of LMU / MPQ Munich
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