Mars had an oxygen-rich atmosphere around 4 billion years ago
13
The Sun and Moon appear to be the same size because the moon is 400 times smaller than the Sun, but 400 times closer to Earth.
13
If you were to cry in space, the tears would form a bubble in your eye until it's so big it moves to another spot on your face.
10
Astronauts cannot burp in space.
232
Saturn's rings are about 500,000 miles in circumference but only about a foot thick.
160
There are approximately 3,500 astronomers in the U.S. - but over 15,000 astrologers.
124
Tidal forces between the Earth and Moon are slowing the Earth down and pushing the Moon further away.
46
Any space vehicle must move at a rate of 7 miles per second in order to escape the earth's gravitational pull.
121