Our Moon

The brightest object in our night sky is the Moon. When ancient people started to watch the sky, it was most likely the moon they studied first.When they realized the moon had a cycle or phases, they made the first calendar. With a calendar, they were able to tell when the best time to plant was, and when to have ceremonies.

The moon is small, only about 1/3 the size of the Earth. The light and dark patches on the moon remind some people of a rabbit and others of the face of a man. The lighter places are rocky and covered with crators. The darker places are large smooth plains formed out of lava. The different areas have Latin names.

The Moon is "locked" into a special kind of motion around the Earth. It rotates on its axis at the same speed that it revolves around the Earth. This is why we always see only one side of the Moon. Astronomers call the side we can see the "nearside" and the side we never see the "farside". It wasn't until the 1960's, when we sent spaceships to fly around the Moon, that we were able to see the other side of the Moon for the first time.

The Moon doesn't make light itself, like the Sun. We only see it because sunlight reflects back to us, sort of like a mirror that relects the light of a lamp. In one month the Moon circles once around the Earth. As it goes around the amount of reflected light we see make it look like it changes shape. These changes are known as phases and repeat in a certain order every month.

It is only a coincidence that the Sun and the Moon look about the same size to us. The Moon is hundreds of times smaller in size than the Sun, but it is also hundreds of times closer to us. It is because of this coincidence that we are able to see a solar eclipse. This happens when the Moon passes right between the Earth and the Sun. Just for a few minutes it can block out the Sun. A lunar eclipse is when the Earth's shadow passes over the Moon. This happens about once every six months.

The Moon is the only place in the Universe, other than the Earth, where a human has walked. Neil Armstron was the first person to walk on the Moon on July 20, 1969. The fact that it is accesible though, meaning we can get to it, doesn't make a full moon rising at sunset any less beautiful or mysterious.