Mars had an oxygen-rich atmosphere around 4 billion years ago
13
The earth travels through space at 660,000 miles per hour.
189
Some asteroids have other asteroids orbiting them.
131
The typical spec of dust that you see floating in the air is half way in size between the Earth and a subatomic particle.
131
It 'snows' metal on Venus.
13
The temperature of the earth's interior increases by 1 degree every 60 feet down.
115
Summer on Uranus lasts for 21 years.
358