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.
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.