Saturn's moon, Mimas, not only looks like the Death Star, it also has a Pac Man heat signature.
15
Sound doesn't travel in space.
255
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
It 'snows' metal on Venus.
13