All About the Moon

Will man ever return to the Moon? Until then, here are interesting Moon facts about our favorite celestial body.

Diameter: 2,160 miles

This is about the distance from Washington, D.C., to the Rocky Mountains.

Average Orbital Speed: 2,287 miles per hour

This number is very close to the Moon's diameter, making it the only known celestial body that moves through space at its own width per hour. This motion is readily visible from Earth, even to the naked eye, as the Moon shifts its position against the background stars.

Synodic Period, or Lunar Month: 29 days, 12 hours, 44 minutes, 2.8 seconds

This is the average period from one new Moon to the next.

Rotation Period: 27 days, 7 hours, 43 minutes, 11.5 seconds

This spin–time of the Moon on its own axis is identical to the time it takes the Moon to revolve around Earth, which is why the Moon always keeps almost the same face toward us.

Mass: 81.3 times smaller than Earth's

Its total mass is 500 quintillion tons.

Albedo: Approximately 0.12

Just 12 percent of the sunlight striking the Moon is reflected; the Moon's surface has about the same shininess as soil. By comparison, the albedo of snow is 0.75, and that of Jupiter, 0.51.

Magnitude: -12.7 in full phase

Each magnitude on the standard scale is 2.5 times brighter than the next; compared with the brightest star, Sirius, whose magnitude is -1.5, the Moon is more than 250,000 times brighter.

Surface Temperatures: Daytime, 235°F typically, 273°F maximum; nighttime, can drop to -275°F

This day/night range of about 500°F is more than five times greater than what is found in extreme desert areas of Earth, but is typical of an airless world.

Distance From the Earth: 238,857 miles (mean)

There are distance variations of over 30,000 miles

Surface Gravity: 5.3 feet per second

On the Moon, an object would fall less than three feet in one second and about 11 feet in 2 seconds. On Earth, an object would fall 64 feet in 2 seconds.

Escape Velocity: 1.48 miles per second

To escape the Moon's gravity, a rocket must achieve a speed of about 1.5 miles per second, or 5,328 miles per hour. To escape Earth, a rocket requires a velocity of nearly 7 miles per second, or 25,000 miles per hour.

Scientists inform us that travel to the Moon will take 3 to 4 days each way for the foreseeable future.