10 Need-to-Know Things About Earth's Moon

10 Need-to-Know Things About Earth's Moon:

If the sun were as tall as a typical front door, Earth would be the size of a nickel and the moon would the size of a green pea.

The moon is Earth's satellite and orbits the Earth at a distance of about 384 thousand km (239 thousand miles) or 0.00257 AU.

Twelve human beings have walked on the moon.

The moon makes a complete orbit around Earth in 27 Earth days and rotates or spins at that same rate, or in that same amount of time. This causes the moon to keep the same side or face towards Earth during the course of its orbit.

The moon is a rocky, solid-surface body, with much of its surface cratered and pitted from impacts.

The moon has a very thin and tenuous (weak) atmosphere, called an exosphere.

The moon has no moons.

The moon has no rings.

More than 100 spacecraft been launched to explore the moon. It is the only celestial a body beyond Earth that has been visited by human beings (The Apollo Program).

The moon's weak atmosphere and its lack of liquid water cannot support life as we know it.

Surface features that create the face known as the "Man in the moon" are impact basins on the moon that are filled with dark basalt rocks.

 Facts & Figures 

Orbit Size Around Earth (semi-major axis)		Metric: 384,400 km English: 238,855 miles Scientific Notation: 3.84400 x 105 km (0.00257 A.U.) By Comparison: 0.00257 x Earth's Distance from the Sun
Average Distance from Earth		Metric: 384,400 km English: 238,855 miles Scientific Notation: 3.844 x 105 km (2.570 x 10-3 A.U.) By Comparison: 0.00257 x Earth's distance from the Sun
Perigee (closest)		Metric: 363,104 km English: 225,623 miles Scientific Notation: 3.631 x 105 km (2.427 x 10-3 A.U.) By Comparison: 0.00243 x Earth's distance from the Sun
Apogee (farthest)		Metric: 405,696 km English: 252,088 miles Scientific Notation: 4.057 x 105 km (2.712 x 10-3 A.U.) By Comparison: 0.00271 x Earth's distance from the Sun
Orbit Circumference		Metric: 2,413,402.16 km English: 1,499,618.58 miles Scientific Notation: 2.413 x 106 km
Average Orbit Velocity		Metric: 3,680.5 km/h English: 2,287.0 mph Scientific Notation: 1,022 m/s By Comparison: 0.034 x Earth
Orbit Eccentricity		0.0554 By Comparison: 3.315 x Earth
Orbit Inclination		5.16 degrees By Comparison: Oscillates roughly 0.15 degrees in 173 days.
Equatorial Inclination to Orbit		6.68 degrees
Mean Radius		Metric: 1737.5 km English: 1079.6 miles Scientific Notation: 1.738 x 103 km By Comparison: 0.2727 x Earth
Equatorial Circumference		Metric: 10,917.0 km English: 6,783.5 miles Scientific Notation: 1.0917 x 104 km
Volume		Metric: 21,971,669,064 km3 Scientific Notation: 2.197 x 1010 km3 By Comparison: 0.020 x Earth
Mass		Metric: 73,476,730,924,573,500,000,000 kg Scientific Notation: 7.3477 x 1022 kg By Comparison: 0.0123 x Earth
Density		Metric: 3.344 g/cm3 By Comparison: 0.607 x Earth
Surface Area		Metric: 37,936,694.79 km2 English: 14,647,439.75 square miles Scientific Notation: 3.793669 x 107 km2 By Comparison: 0.074 x Earth
Surface Gravity		Metric: 1.624 m/s2 English: 5.328 ft/s2 Scientific Notation: 1.624 m/s2 By Comparison: 0.166 x Earth
Escape Velocity		Metric: 8,552 km/h English: 5,314 mph Scientific Notation: 2,376 m/s By Comparison: 0.212 x Earth
Sidereal Rotation Period (Length of Day)		27.322 Earth days 655.73 hours By Comparison: Synchronous with Orbital Period
Minimum/Maximum Surface Temperature		Metric: -233/123 °C English: -387/253 °F Scientific Notation: 40/396 K