Moon: The Whole Story

Only one moon orbits Earth; it is a stony, cratered body that is about one-quarter the size of Earth and is located on average 238,855 miles distant. The Moon travels a 27-day orbit around our planet and is typically visible with the unaided eye.

Probably one of the first images that come to mind when you think of the night sky is the Moon "glowing" in the shadows. The Moon has always had a special position in both our daily lives and our imaginations.

Being interested is nothing to be shocked about. Most nights, it is possible to see the Moon, the only naturally occurring satellite of Earth.

What makes the Moonglow?

The Moon doesn't emit any light of its own. It only acts as a reflector of sunlight.

Why does it seem like the Moon is changing shape?

When viewed from Earth, the Moon may appear to change shape every night, going from a tiny sliver to a half moon to a full moon and back again. Actually, from Earth, we can see different areas of the Moon being lighted by the Sun as it moves through its orbit.

Does the Moon really have a "black side"?

No. At the same rate, as it orbits the Earth, the Moon revolves around its own axis. That implies that from our vantage point on Earth, we constantly see the same side of the Moon. The "far side" is a more appropriate term to describe the side of the Moon that humans cannot see because it receives equal amounts of light.

How was the Moon created?

The Moon is thought to have originated early in the history of the solar system after an object the size of Mars and Earth collided. The Moon was formed when the impactor and pieces of Earth were sent into space and brought together by gravity.

How can the Moon be studied?

Humans have been drawing images of the Moon's variations for thousands of years. Calendars were later made using observations of the Moon.

Today, telescopes and satellites are used to investigate the Moon. For instance, since 2009, NASA's Lunar Reconnaissance Orbiter has been orbiting the Moon and transmitting measurements.

The only other planet that has been visited by mankind is the Moon. Neil Armstrong and Buzz Aldrin, NASA astronauts, were the first to set foot on the lunar surface on July 20, 1969. Ten further American astronauts came after. They performed research, built equipment for further measurements, and gathered hundreds of pounds of lunar soil and rock samples.

What details do we know about the Moon?

We now know that the Moon is covered in craters as well as dust and debris from impacts with comets, asteroids, and meteoroids. We are aware that the Moon's shadowy regions, known as maria—the Latin word for seas—are not literally seas. They are actually craters where lava has crept into over the course of billions of years. We are aware of the Moon's low gravity and nearly non-existent atmosphere. Even more, we are aware that there is a significant amount of frozen water hidden away in craters close to the Moon's poles.

 Regarding the Moon, there are still a lot of unanswered questions. And as NASA sends people on upcoming missions to the Moon and eventually to Mars, the most intriguing lunar activity may still be yet to come!