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
Sound doesn't travel in space.
255
The Space Shuttle main engine weighs 1/7th as much as a train engine but delivers as much horsepower as 39 locomotives.
147
The last time that the Sun was in its current position in space around the Milky Way, dinosaurs ruled the Earth.
10
Summer on Uranus lasts for 21 years.
358
An organisation called Mars One is planning to establish a permanent colony of humans on Mars by 2023.
9