If two pieces of metal touch in space, they become permanently stuck together.
808
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
Tidal forces between the Earth and Moon are slowing the Earth down and pushing the Moon further away.
46
Mars had an oxygen-rich atmosphere around 4 billion years ago
13
The Space Shuttle main engine weighs 1/7th as much as a train engine but delivers as much horsepower as 39 locomotives.
147
Any space vehicle must move at a rate of 7 miles per second in order to escape the earth's gravitational pull.
121
An international team of astronomers has spotted the farthest known gravitational lens and, as Albert Einstein predicted, it is a galaxy that deflects and intensifies the light of a much further object.
9