Mars had an oxygen-rich atmosphere around 4 billion years ago
13
A comet's tail always points away from the sun.
2
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
There is a mysterious and loud radio signal known as 'the space roar' that has yet to be explained.
15
Pluto is smaller than Russia.
9
One pinhead of the sun's energy is enough to kill a person at a distance of 160 kilometers.
277
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