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  2. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    More exactly, sidereal time is the angle, measured along the celestial equator, from the observer's meridian to the great circle that passes through the March equinox (the northern hemisphere's vernal equinox) and both celestial poles, and is usually expressed in hours, minutes, and seconds. (In the context of sidereal time, "March equinox" or ...

  3. Rotation period (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Rotation_period_(astronomy)

    176 days [4] Venus: −243.0226 days [ii] [5] −243 d 0 h 33 m: −116.75 days [6] Earth: 0.99726968 days [3] [iii] 0 d 23 h 56 m 4.0910 s: 1.00 days (24 h 00 m 00 s) Moon: 27.321661 days [7] (equal to sidereal orbital period due to spin-orbit locking, a sidereal lunar month) 27 d 7 h 43 m 11.5 s: 29.530588 days [7] (equal to synodic orbital ...

  4. Earth's rotation - Wikipedia

    en.wikipedia.org/wiki/Earth's_rotation

    Thus, the sidereal day is shorter than the stellar day by about 8.4 ms. [37] Both the stellar day and the sidereal day are shorter than the mean solar day by about 3 minutes 56 seconds. This is a result of the Earth turning 1 additional rotation, relative to the celestial reference frame, as it orbits the Sun (so 366.24 rotations/y).

  5. Day - Wikipedia

    en.wikipedia.org/wiki/Day

    A sidereal day or stellar day is the span of time it takes for the Earth to make one entire rotation [5] with respect to the celestial background or a distant star (assumed to be fixed). [6] Measuring a day as such is used in astronomy. [6] A sidereal day is about 4 minutes less than a solar day of 24 hours (23 hours 56 minutes and 4.09 seconds ...

  6. Synodic day - Wikipedia

    en.wikipedia.org/wiki/Synodic_day

    A synodic day (or synodic rotation period or solar day) is the period for a celestial object to rotate once in relation to the star it is orbiting, and is the basis of solar time. The synodic day is distinguished from the sidereal day , which is one complete rotation in relation to distant stars [ 1 ] and is the basis of sidereal time.

  7. Diurnal motion - Wikipedia

    en.wikipedia.org/wiki/Diurnal_motion

    The time for one complete rotation is 23 hours, 56 minutes, and 4.09 seconds – one sidereal day. The first experimental demonstration of this motion was conducted by Léon Foucault. Because Earth orbits the Sun once a year, the sidereal time at any given place and time will gain about four minutes against local civil time, every 24 hours ...

  8. Solar time - Wikipedia

    en.wikipedia.org/wiki/Solar_time

    On a prograde planet like the Earth, the sidereal day is shorter than the solar day. At time 1, the Sun and a certain distant star are both overhead. At time 2, the planet has rotated 360° and the distant star is overhead again (1→2 = one sidereal day). But it is not until a little later, at time 3, that the Sun is overhead again (1→3 = one solar day). More simply, 1→2 is a complete ...

  9. Time standard - Wikipedia

    en.wikipedia.org/wiki/Time_standard

    A sidereal rotation is the time it takes the Earth to make one revolution with rotation to the stars, approximately 23 hours 56 minutes 4 seconds. A mean solar day is about 3 minutes 56 seconds longer than a mean sidereal day, or 1 ⁄ 366 more than a mean sidereal day. In astronomy, sidereal time is used to predict when a star will reach its ...