The time between two consecutive transits of the First Point of Aries. It represents the time taken by the earth to rotate on its axis relative to the stars, and is almost four minutes shorter than the solar day because of the earth's orbital motion.
〔天文〕恒星日
Example sentencesExamples
These sessions were performed during two consecutive days but delayed by 4 minutes per day, since the satellite sky distribution is repeated with a period close to a sidereal day.
The reason that sidereal days are shorter is that while the Earth rotates on its axis, it is also moving around the Sun.
Over the past few sidereal days more radio signals from an as-yet-unidentified source have been detected.
I understand the concepts of the sidereal day, and am happy with my intuitive notions of the Earth's rotation and movement relative to the sun and the solar system.
Even the closest star to us is so far away that the sidereal day is the same, no matter what star you use to measure it.
Synonyms
twenty-four-hour period, full day, twenty-four hours, working day
Definition of sidereal day in US English:
sidereal day
noun
Astronomy
The time between two consecutive transits of the First Point of Aries. It represents the time taken by the earth to rotate on its axis relative to the stars, and is almost four minutes shorter than the solar day because of the earth's orbital motion.
〔天文〕恒星日
Example sentencesExamples
The reason that sidereal days are shorter is that while the Earth rotates on its axis, it is also moving around the Sun.
These sessions were performed during two consecutive days but delayed by 4 minutes per day, since the satellite sky distribution is repeated with a period close to a sidereal day.
Over the past few sidereal days more radio signals from an as-yet-unidentified source have been detected.
I understand the concepts of the sidereal day, and am happy with my intuitive notions of the Earth's rotation and movement relative to the sun and the solar system.
Even the closest star to us is so far away that the sidereal day is the same, no matter what star you use to measure it.
Synonyms
twenty-four-hour period, full day, twenty-four hours, working day