Time standard · UT1
Universal Time (UT1)
The form of Universal Time tied to the actual rotation of the Earth, measured from the positions of distant sources. Because the Earth's spin is slightly irregular and slowly slowing, UT1 drifts against the steady beat of atomic time.
Bodies, frames & concepts
Across celestial mechanics
Knowledge connections
- Associated withSidereal Time
- Associated withCoordinated Universal Time (UTC)
- Associated withThe Leap Second
- Associated withSidereal Time
- Associated withEarth Orientation Parameters
- Associated withInternational Earth Rotation and Reference Systems Service (IERS)
Sources
The primary and reference sources this topic draws on.
- US Naval ObservatoryUnited States Naval Observatory
Precise time, almanac data, Sun/Moon rise-set, and phases.