Number 215 (Story #1), February 24, 1995 by Phillip F. Schewe and Ben Stein CESIUM ATOMS HAVE BEEN COOLED TO 700 NANOKELVINS , the lowest 3D temperatures ever achieved in an atom. Researchers at NIST (contact William Phillips at 301- 975-6554) make special laser light patterns called "optical lattices" which trap pre-cooled atoms at regular locations in the pattern. Then, by gradually decreasing the intensity of the laser light, they diminish interactions between light's electric field and the atom. This causes each atom to occupy a larger region of space. In "expanding" to their new volume, the atoms expend energy, making them colder. Such supercold atoms may someday be employed to make more accurate atomic clocks and atomic interferometers. (Physical Review Letters, 27 February 1995.)