The Moon is Earth’s satellite, a pitted rocky body orbiting the planet. It has no light of its own, but seems bright in the sky due to the reflection of the Sun. The Moon’s surface was cratered by bodies that crash into it between 3 and 4 billion years ago, and exploded on it’s surface.
Despite the closeness of the Moon to the Earth, scientists are still unable to be sure how this satellite was created. A century ago, it was speculated that the molten Earth, spinning very fast, became unstable and throw a mass of lava into its own orbit.
Now it is believed that a small body collided with the Earth at a slanted angle. The cores of the two planets combined, and the outer crust and the mantle were thrown outward into cloud of material that began to orbit the planet. Over time, this cloud of material collected together into what we now know as the Moon.
Rock samples brought back to Earth from the Apollo Moon mission contained the same oxygen ratios as that Earth, so scientists hypothesize the Earth and the Moon were at one time a single object.
The side of the Moon that faces Earth has huge ancient lave plains, called maria, and the Earth’s gravity strained and weakened this side pulling it out of shape. As a result lava flowed out of the cracks in the crust to form the lave plains.
The far side side, or dark side of the Moon is covered in craters and mountain ranges, they were not cause by movements in the crust. There are surviving walls of ancient craters.
Because the Moon has an elliptical orbit, it is not always the at distance from the Earth. The point when the moon is at its closest is called a perigee and when it at its furthest it is called it apogee.
There are 8 distinct continual phases of the Moon, and on average, lasts 29.5 days. as it orbits the Earth they are;
1. New Moon – When it is not illuminated by direct sunlight.
2. Waxing Crescent – The Moon is less than one half illuminated.
3. First Quarter – Only 1/2 of the Moon is illuminated.
4. Waxing Gibbous - The Moon is more than 1/2 illuminated.
5. Full Moon - The Moon is fully illuminated.
6. Waning Gibbous - The Moon is more than 1/2 illuminated, with the illuminated part decreasing.
7. Last Quarter – 1/2 of the Moon appears illuminated, with the illuminated part decreasing.
8. Waning Crescent - The Moon is less than 1/2 illuminated, with the illuminated part decreasing.