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
The Space Shuttle main engine weighs 1/7th as much as a train engine but delivers as much horsepower as 39 locomotives.
147
If aliens located 60-65 million light years away from us, looked at earth through a really powerful telescope today, they would see dinosaurs!
18
The last time that the Sun was in its current position in space around the Milky Way, dinosaurs ruled the Earth.
10
On Titan, Saturn's largest moon, the atmosphere is so thick and the gravity so low that humans could fly through it by flapping "wings" attached to their arms.
7
An organisation called Mars One is planning to establish a permanent colony of humans on Mars by 2023.
9