“Absolute zero” isn't just cold — it's still. It is the point at which the motion of the atoms that make up an object stops completely, when the object has no energy left to give.
The rules of physics say it's impossible to cool an object to absolute zero, to remove all thermal energy until its atoms come to a standstill. But researchers at the National Institute of Standards and Technology are getting really close. In a paper published Wednesday in the journal Nature, they describe using a laser to make a microscopic aluminum drum colder than anything like it has been cooled before. In doing so, they defied the quantum limit for supercooling mechanical objects.
