sidereal day
- noun
- /saɪˈdɪəriəl deɪ/
- Specialized
:
día sidéreo
- Twenty-three hours and 56 minutes is the length of a sidereal day (a day measured relative to the stars), as distinct from the solar day, which is 24 hours long.
One full revolution, OK, OK, That's called a sidereal day.
- One full revolution, OK, OK, That's called a sidereal day.
Examples
-
This is a bit longer than the sidereal day—the time required for the equivalent apparent motion of the "fixed" stars.
Blog text (11) -
Because Earth is simultaneously orbiting the Sun, the sidereal day is shorter than the solar day.
Academic text (2007) -
But there is also the sidereal day.
Academic text (2007) -
But there is also a duration known as the sidereal day.
Academic text (2007) -
If you think about the physical situation, you will realize that the sidereal day must be shorter than the solar day.
Academic text (2007) -
A sidereal day lasts approximately 23 hours, 56 minutes, and 4 seconds.
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Astronomers measure a sidereal day by observing the position of distant stars.
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The difference between a sidereal day and a solar day is about four minutes.
Antonyms
- Specialized
Average time for Earth to turn once so the Sun appears in the same place, about 24 hours
Surface Forms
Morphology
The adjective 'sidereal' means 'relating to the stars' and 'day' denotes a rotation period; combined, they transparently yield 'a day measured with respect to the stars' (i.e., a rotation relative to distant stars). This compositional, modifier+noun structure is predictable and has direct parallels in other languages, so a learner who knows both constituents can infer the MWE's meaning.
Etymology
The noun sidereal day comes from watching the stars: sidereal refers to the stars and day means one full turn of the Earth. It is the time the Earth needs for the same distant star to return to the same place in the sky, about 23 hours 56 minutes, so it is a little shorter than the usual 'solar day'.