Science ❯ Physics

Time Measurement

Atomic Clocks Chronobiology Chronology Daylight Saving Time Chronometry Time Standards Equation of Time Atomic Physics Leap Seconds Standards Standards Organizations Atomic Time Technological Standards Optical Clocks Universal Time Coordinated (UTC) Gravitational Time Dilation Attoseconds Standards of Time Seasonal Changes Technological Applications Optical Lattice Clocks Temporal Changes Circadian Rhythms Time Signals Day Duration Attosecond

NIST Restores U.S. Time After Colorado Outage Causes Microsecond Drift

A generator failure during a utility shutoff caused the microsecond drift, now corrected.

Winter Solstice Arrives Sunday at 3:03 p.m. GMT, Marking Year’s Shortest Day

Record-Short Days Renew Debate Over First-Ever Negative Leap Second

Earth Sets Second-Shortest Day of 2025 as Spin Continues to Accelerate

New Projections Confirm Record-Short Days This July and August

Earth's Spin Breaks Short-Day Records as Timekeepers Halt 2025 Leap Second