The Planet Mercury

Mercury as seen by Mariner 10

Planet	Mercury
Radius (kilometers)	2439
Orbital Distance from the Sun (kilometers)	57909141
Rotation Period (1=24 hours)	58.646
Mass (Million Metric Tons)	3.302E+11
Density (grams/cubic centimeter)	5.43
Year Discovered	Unknown
Moons	0

Mercury has the longest day of any planet. One day on Mercury is 4,222 hours long.
While Mercury has the longest day due to its slow rotation, Mercury is the fastest moving of the planets. It orbits the Sun at an average speed of 48 kilometers per second.

Need someone to talk about space to your group? Check out the Chicago Society for Space Studies Speakers Bureau

For space art, astronomy, and digital photography stories, visit the Artsnova Blog