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
Pluto is smaller than Russia.
9
If two pieces of metal touch in space, they become permanently stuck together.
808
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
Sound doesn't travel in space.
255
From the nitrogen in our DNA, to the calcium in our teeth, the iron in our blood, to the carbon in our apple pies - all were made in the interiors of collapsing stars; we're all made of stardust.
22
A comet's tail always points away from the sun.
2