|The Boomerang Nebula is the coldest natural object known in the universe, seen here by the Hubble Space Telescope (Image: ESA/NASA)|
"In everyday solids, liquids and gases, heat or thermal energy arises from the motion of atoms and molecules as they zing around and bounce off each other. But at very low temperatures, the odd rules of quantum mechanics reign. Molecules don't collide in the conventional sense; instead, their quantum mechanical waves stretch and overlap. When they overlap like this, they sometimes form a so-called Bose-Einstein condensate, in which all the atoms act identically like a single "super-atom". The first pure Bose-Einstein condensate was created in Colorado in 1995 using a cloud of rubidium atoms cooled to less than 170 nanokelvin."
(from: New Scientist article on Feb 2010.)