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
Sound doesn't travel in space.
255
The density of Saturn is so low that if you were to put it in a giant glass of water it would float.
219
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 is a mysterious and loud radio signal known as 'the space roar' that has yet to be explained.
15