41% of the moon is not visible from earth at any time.
103
A 100-pound person on Earth would weigh 38 pounds on Mars.
102
The density of Saturn is so low that if you were to put it in a giant glass of water it would float.
219
A car traveling 100 mph would take more than 29 million years to reach the nearest star (to our solar system)
88
There are approximately 3,500 astronomers in the U.S. - but over 15,000 astrologers.
124
The Earth weighs around 6,600,000,000,000,000,000,000 tons (5,940 billion billion metric tons)!
221
Mars had an oxygen-rich atmosphere around 4 billion years ago
13