universal time
Sign in to savetime standard based on the Earth's rotation
In the Vinony graph
Vinony's link graph records 552 inbound references to universal time, and connects out to geologic time scale, sidereal time and solar time.
It sits within the topics Time in astronomy and Time scales.
Vinony links it to 43 Wikipedia language editions.
Wikidata facts
- Instance of
- time standard
Show 4 more facts
- replaced by
- ephemeris time
- replaces
- Greenwich Mean Time
- on focus list of Wikimedia project
- Wikipedia:Vital articles/Level/4
Sources (2)
via Wikidata · CC0
~13 min read
Encyclopedic overview
Universal Time (UT or UT1) is a time standard based on Earth's rotation. While originally it was mean solar time at 0° longitude, precise measurements of the Sun are difficult. Therefore, UT1 is computed from a measure of the Earth's angle with respect to the International Celestial Reference Frame (ICRF), called the Earth Rotation Angle (ERA, which serves as the replacement for Greenwich Mean Sidereal Time). UT1 is the same everywhere on Earth. UT1 is required to follow the relationship
ERA = 2π(0.7790572732640 + 1.00273781191135448 · Tu) radians
Excerpted from Wikipedia’s “universal time” article, available under the CC BY-SA 4.0 licence.