More than 20 million meteoroids enter Earth's atmosphere every day.
139
Any space vehicle must move at a rate of 7 miles per second in order to escape the earth's gravitational pull.
121
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
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
The earth rotates more slowly on its axis in March than in September.
145
The heart of an astronaut actually gets smaller when in outer space.
216