The Moon

The moon is the only natural satellite orbiting Earth and the Earth's closest neighbor in space. This cold, rocky body is about 384,403 kilometers (238, 857 miles) away. This distance is similar to going around the earth 10 times.

The moon is 3476 kilometers (2,160 miles) in diameter. It is 1/4 the size of the earth. It is about 400 times smaller than the sun and 400 times closer. For this reason the sun and moon appear to be the exact same size.

The moon is very old!!! Scientists believe that about 4.5 billion years ago a Mars-sized body hit Earth and the resulting debris (from both Earth and the impacting body) accumulated to form the Moon. Scientists know this because they studied the lunar rocks that were collected by astronauts who went to the moon. The moon and the earth are made of the same material.

You can read more about the moon at NASA's StarChild, A Learning Center for Young Astronomers.

The daily maximum temperature is 250° F (hot enough to boil water). At night the temperature can reach -250° F.

Picture courtesy of NASA

Picture courtesy of NASA

The Moon has no atmosphere so the lunar sky is black. You need atmosphere to make the sky blue. Astronauts must carry their own air for breathing when they visit the moon.

The surface of the moon is covered in craters or holes that have been created by space rocks or meteors that hit the soil. The lack of atmosphere there allows the rocks to crash into the surface. An atmosphere would protect - just as it does here on the earth.

Funny stuff: Did you hear the one about the restaurant on the moon?

The food is terrific, but there's no atmosphere.

Picture courtesy of NASA

Ice exists in some deep craters near the Moon's south pole which are permanently shaded. This was confirmed by Lunar Prospector. There is probably ice at the north pole as well.

If you weigh 60 pounds on earth, you would weigh 10 pounds on the moon because gravity is 1/6th as strong on the moon.

The same side of the moon always faces Earth which means that when we look up into the sky we can only see one side.

Below is a NASA photo of the far side of the moon. Until space travel was possible, no one had seen this side of the moon.

Picture courtesy of NASA

The moon has no light of its own. It shines because sunlight is reflected from its surface.

What is "moonrise?" The Earth rotates once a day on its axis causing the phenomena of the rising and setting of the sun and moon. They seem to appear in the sky at the horizon to the East, then to cross the sky and disappear at the horizon to the West. Photo

The moon orbits, or revolves, around the Earth about once every 27 days, 7 hours, 43 minutes. This movement causes the moon to cycle through a series of phases: New, New Crescent, First Quarter, Waxing Gibbous, Full, Waning Gibbous, Last Quarter, Old Crescent and back to New again.

Ask Dr. Marc: How long does each phase of the moon last? Check out these sites: Phases from Starchild or Phases of the Moon

Sometimes the moon passes through some portion of the earth's shadow and the Earth blocks part or all of the sun's rays from reaching the moon. This is called a lunar eclipse and can only occur at Full Moon. Now you are ready to learn about a Lunar Eclipse from NASA. A schedule of upcoming eclipses can be found on NASA's website.

Almost three hundred sixty years after the Italian astronomer Galileo Galilei made his first observation of the Moon with a telescope in 1610, the Apollo 11 mission made the first landing on the Moon and returned samples in 1969.

Don't miss the great Apollo 11 story from NASA complete with audio, video, and photos. Here is a chronology of man's lunar visits.

The moon missions brought back 382 kilograms (840 pounds) of soil and rock from the moon.

A close-up view of an astronaut's footprint in the lunar soil. Courtesy of NASA. Click here for more photos.