Things that are cool: Astrophysics
The sun is really big. Its really hard to get across the sheer incomprehensible bigness of these things, but sometimes you come across numbers that really brings it home:
Here is one: The sun creates light by converting mass into energy through fusion. Since the creation of the earth some 4.7bn years ago, the sun has converted roughly the total mass of the earth into energy. (6*10^24 Kilograms). This is a negligible proportion of the suns mass of 2*10^30kg.