If two pieces of metal touch in space, they become permanently stuck together.
808
Summer on Uranus lasts for 21 years.
358
Sound doesn't travel in space.
255
An organisation called Mars One is planning to establish a permanent colony of humans on Mars by 2023.
9
It takes a photon 170,000 years to travel from the core of the Sun to the surface, but only 8 minutes to travel the rest of the way to Earth.
6
If NASA sent birds into space they would soon die; they need gravity to swallow.
146
Earth is the only planet in our solar system that's not named after a god or goddess.
17