Earth's rotation
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Earth's rotation or Earth's spin is the rotation of planet Earth around its own axis, as well as changes in the orientation of the rotation axis in space. Earth rotates eastward, in prograde motion. A
This long-exposure photo of the northern night sky above the Nepali Himalayas shows the apparent paths of the stars as Earth rotates.
Starry circles arc around the south celestial pole, seen overhead at ESO's La Silla Observatory.
An artist's rendering of the protoplanetary disk
Sidereal time
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Sidereal time is a system of timekeeping used especially by astronomers. Using sidereal time and the celestial coordinate system, it is easy to locate the positions of celestial objects in the night s
Earth's rotation
…at which Earth's axis of rotation intersects its surface, in Antarctica. Earth rotates once in about 24 hours with respect to the Sun, but once every 23 hours, 56 minutes, and 4 seconds with respect to other distant stars (see below). Earth's rotation is slowing slightly with time; thus, a day was shorter in the past. This is due to…
One of the two known surviving sidereal angle clocks in the world, made by John Arnold & Son. It was previously owned by Sir George Shuckburgh-Evelyn. It is on display in the Royal Observatory, Greenwich, London.
Marine sandglass MMM