Rotation period

In astronomy, a rotation period is the time an astronomical object takes to complete one revolution around its rotation axis relative to the background stars. For the Earth this is a sidereal day. It is different from a solar day, which is measured by the passage of the Sun across the local meridian.

All celestial objects spin.Why and how do planets rotate?. Scientific American. 14 April 2003.Ethan Siegel 2019. This is why black holes must spin at almost the speed of light. Forbes.Robert Walty 2019. It is said that most black holes likely have spin. What exactly is it that spins?. astronomy.com. The rotation period differs according to whether the body in question is solid or fluid (gaseous). A solid object has one value, but a fluid object such as a star spins differently at the poles compared to the equator (Sun: about 25 days at the equator and about 35 days near the poles). Zell, Holly 2015. Solar rotation varies by latitude. NASA.Beck J. 2000. A comparison of differential rotation measurements. Solar Physics. 191: 47–70. Bibcode:2000SoPh..191...47B.doi:10.1023/A:1005226402796

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Category:Celestial mechanics