Which planet in our solar system has the shortest day?

McGruff

Jupiter has the shortest rotational (spin) period, about 9 hours, 55 minutes, 30 seconds. http://www.enchantedlearning.com/subjects/astronomy/planets/ http://www.astrophys-assist.com/educate/robot/page11.htm Jul 23 00, 3:47 PM

DPISHERE

Jupiter. Because Jupiter is not a solid body, its upper atmosphere undergoes differential rotation. The rotation of Jupiter's polar atmosphere is about 5 minutes longer than that of the equatorial atmosphere; three "systems" are used as frames of reference, particularly when graphing the motion of atmospheric features. System I applies from the latitudes 10° N to 10° S; its period is the planet's shortest, at 9h 50m 30.0s. System II applies at all latitudes north and south of these; its period is 9h 55m 40.6s. System III was first defined by radio astronomers, and corresponds to the rotation of the planet's magnetosphere; its period is Jupiter's "official" rotation. http://en.wikipedia.org/wiki/Jupiter [Added text - McG] Jul 28 08, 3:03 PM