Mars had an oxygen-rich atmosphere around 4 billion years ago
13
If aliens located 60-65 million light years away from us, looked at earth through a really powerful telescope today, they would see dinosaurs!
18
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
Summer on Uranus lasts for 21 years.
358
It takes a photon 170,000 years to travel from the core of the Sun to the surface, but only 8 minutes to travel the rest of the way to Earth.
6
The density of Saturn is so low that if you were to put it in a giant glass of water it would float.
219
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