Astronomer Percival Lowell believed that he was the first person to observe canals on Venus, but because of a faulty adjustment of the eyepiece on his telescope, he was in fact looking at the blood vessels in his own eye.
4
Any space vehicle must move at a rate of 7 miles per second in order to escape the earth's gravitational pull.
121
41% of the moon is not visible from earth at any time.
103
On Titan, Saturn's largest moon, the atmosphere is so thick and the gravity so low that humans could fly through it by flapping "wings" attached to their arms.
7
The temperature of the earth's interior increases by 1 degree every 60 feet down.
115
A lightning bolt generates temperatures five times hotter than those found at the sun's surface!
127
Mars had an oxygen-rich atmosphere around 4 billion years ago
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