If two pieces of metal touch in space, they become permanently stuck together.
808
From the nitrogen in our DNA, to the calcium in our teeth, the iron in our blood, to the carbon in our apple pies - all were made in the interiors of collapsing stars; we're all made of stardust.
22
Summer on Uranus lasts for 21 years.
358
Mars had an oxygen-rich atmosphere around 4 billion years ago
13
One pinhead of the sun's energy is enough to kill a person at a distance of 160 kilometers.
277
Saturn's moon, Mimas, not only looks like the Death Star, it also has a Pac Man heat signature.
15
A comet's tail always points away from the sun.
2