Mars had an oxygen-rich atmosphere around 4 billion years ago
13
Only 55% of Americans know that the sun is a star.
986
The Space Shuttle main engine weighs 1/7th as much as a train engine but delivers as much horsepower as 39 locomotives.
147
If you were to cry in space, the tears would form a bubble in your eye until it's so big it moves to another spot on your face.
10
The Sun and Moon appear to be the same size because the moon is 400 times smaller than the Sun, but 400 times closer to Earth.
13
In space, astronauts cannot cry properly, because there is no gravity, so the tears can't flow down their faces!
175
The density of Saturn is so low that if you were to put it in a giant glass of water it would float.
219
More than 20 million meteoroids enter Earth's atmosphere every day.
139