Terrestrial Time (Noun)
Meaning
(astronomy) a measure of time defined by Earth's orbital motion; terrestrial time is mean solar time corrected for the irregularities of the Earth's motions.
Classification
Nouns denoting time and temporal relations.
Examples
- The astronomical unit is used as a standard unit of length in calculating terrestrial time.
- In the field of astronomy, terrestrial time is a modern continuation of what used to be called Ephemeris Time.
- A new definition of the second in terms of the caesium frequency standard replaced the standard based on the Earth's rotation for use in the modern continuation of terrestrial time.
- Ephemeris time and terrestrial time have since been replaced as precision time standards by International Atomic Time and its derivatives.
- International System of Units defined one second of terrestrial time as equal to the time it takes a caesium-133 atom to perform 9,192,631,770 vibrations.