Objects are easier to study when they stay still than when they are in motion. Atoms-even the ones in solids-are always moving. NIST pioneered the use of lasers to cool atoms to temperatures barely above absolute zero. This slows them down almost to a standstill.

Laser light exerts tiny forces on atoms. By aligning six laser beams at right angles in the center of a vacuum chamber, NIST scientists can restrict the atoms' movement and make them very cold. This research has allowed substantial advances in atomic timekeeping as well as other breakthroughs in basic atomic physics.