Moon Facts
(for Moonquest! The Adventure Begins)

Fact:
Like the rest of the Solar System, the Moon is about 4 1/2 billion years old. Most of the cratering occurred in the first billion years of its life, when leftover debris from planet formation was abundant. 

Fact:
The same side of the Moon always faces the Earth. (The Moon's rotation period is synchronous with its revolution period around the Earth). 

Fact:Animation of Moon phases
Because of a loss of orbital energy to gravity from the Earth, the Moon is very gradually moving away from the Earth. In the early history of the Earth, the Moon looked about 3 times larger in apparent size in the sky, because it was closer to the Earth. 

Fact:
The dark looking "seas" on the Moon are really smoother and darker colored rock that came from volcanic flows early in the history of the moon after most of the cratering had occurred. These dark spots are called "Maria". 

Fact:
There are few "seas" on the back (far) side of the Moon (the side opposite Earth). 
 

Fact:
The Moon is only one-fourth the diameter of the Earth. 

Fact:
The Moon has almost no atmosphere, because of its weak gravity. All types of gas will escape from its surface. The surface temperature fluctuates from roughly + 300 F during the 2-week daytime to -270 F during the 2-week night.  This is because there is not enough atmosphere to keep the Moon warm at night, nor protect it from the Sun's rays in the daytime. 

Fact:
Without an atmosphere, there is no wind or water erosion. The Moon's surface is about the same now as it was 3 billion years ago. (Contrast to the Earth). The astronauts' footprints remain unchanged on the Moon's surface, and will until the Moon is struck by an asteroid. 

Want to find other Facts about the Moon?  Check out some of these links...

Star Child: Level One and Level Two

Our Moon - from Windows to the Universe 

Lunar History

Moon Facts 

Frequently Asked Questions about Lunar Prospector and the Moon 



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