Mars had an oxygen-rich atmosphere around 4 billion years ago
13
Sound doesn't travel in space.
255
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82
There is a mass reservoir of water floating in space that is 100,000 times bigger than our sun and holds 140 trillion times more water than all of our oceans.
11
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
Tidal forces between the Earth and Moon are slowing the Earth down and pushing the Moon further away.
46
If NASA sent birds into space they would soon die; they need gravity to swallow.
146