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
Mars had an oxygen-rich atmosphere around 4 billion years ago
13
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 last time that the Sun was in its current position in space around the Milky Way, dinosaurs ruled the Earth.
10