Eclipse

Awesome pic of the sun's Corona from a recent total solar eclipse. Fun facts: It is entirely co-incidental that the moon can perfectly eclipse the sun. There is no reason that the moon is the precise size at the precise distance to block out the sun perfectly, other than luck (or a process no one yet has any idea about). That said, the moon is moving further and further away from the Earth every year - every moment, actually - such that, in a billion years or so, the moon will no longer perfectly block the sun.

Also cool is the Corona itself, which we could only see for a long, long time during an eclipse (We can see it anytime we want now thanks to the fleet of satellites monitoring the sun). Strange fact: The Corona extends pretty far out into space, yet it is far, far hotter than the surface of the sun. Also, in the picture above, you're essentially looking at the layout of the sun's magnetic field, with the ejected energy/matter of the sun streaming along these magnetic lines.

Here's another cool pic of the recent eclipse: