The heart of an astronaut actually gets smaller when in outer space.
216
Sound doesn't travel in space.
255
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
There's a mysterious dwarf planet between Mars and Jupiter called 'Ceres' which has never been visited by spacecraft or photographed in detail, however, Earth-bound telescopes reveal a large bright shining spot on the surface of this planet, the origin and nature of which are unknown.
5
Buzz Aldrin’s mother’s maiden name was Moon.
9
There are 5 to 10 times more stars in the known Universe than there are grains of sand on all the world's beaches, but a single grain of sand has more atoms than there are stars in the known Universe.
20
Astronomer Percival Lowell believed that he was the first person to observe canals on Venus, but because of a faulty adjustment of the eyepiece on his telescope, he was in fact looking at the blood vessels in his own eye.
4