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 population of the Earth has more than doubled since 1950.
151
A neutron star (what remains after a Super Nova) is so dense that a portion of it the size of a sugar cube would weigh as much as all of humanity, or more than all the cars in the United States.
5
41% of the moon is not visible from earth at any time.
103
A comet's tail always points away from the sun.
2