Saturn's rings are about 500,000 miles in circumference but only about a foot thick.
160
Only 55% of Americans know that the sun is a star.
986
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
An organisation called Mars One is planning to establish a permanent colony of humans on Mars by 2023.
9
Pluto is smaller than Russia.
9
The population of the Earth has more than doubled since 1950.
151
41% of the moon is not visible from earth at any time.
103
The last time that the Sun was in its current position in space around the Milky Way, dinosaurs ruled the Earth.
10