What is Rotation period?
In [[astronomy]], a '''rotation period''' is the [[time]] an [[astronomy|astronomical]] [[object]] takes to complete one [[revolution]] around its rotation [[Axis (mathematics)|axis]] relative to the background [[star]]s. 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 (geography)|meridian]]. All celestial objects spin.<ref>Why and how do planets rotate?. Scientific American. 14 April 2003. </ref><ref>Ethan Siegel 2019. This is why black holes must spin at almost the speed of light. ''Forbes''. </ref><ref>Robert Walty 2019. It is said that most black holes likely have spin. What exactly is it that spins?. astronomy.com. </ref> 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).<ref> Zell, Holly 2015. Solar rotation varies by latitude. '''NASA'''.[https://www.nasa.gov/mission_pages/sunearth/science/solar-rotation.html]</ref><ref>Beck J. 2000. A comparison of differential rotation measurements. ''Solar Physics''. '''191''': 47–70. Bibcode:2000SoPh..191...47B.doi:10.1023/A:1005226402796</ref> == Related pages == *[[Tidal locking]] ==Other websites== * {{cite web | title=MIRA | work=Jupiter| url=http://www.mira.org/fts0/planets/099/text/txt001x.htm| accessdate=2005-05-24}} == References == {{reflist}} {{Sci-stub}} [[Category:Celestial mechanics]]