Solar eclipses are relatively rare events on the Earth's surface. The Moon's orbit around the Earth is tilted a bit with respect to the Earth's orbit around the Sun, so the Moon has to be at the right place at the right time to block the Sun.
But what if you're in orbit around the Earth? In that case, the Earth itself
blocks the Sun all the time (of course, if you want to be pedantic, it happens to us on the surface every time the Sun sets). NASA's Solar Dynamics Observatory stares at the Sun 24/7/365, and was placed in an orbit to minimize the amount of time the Earth blocks its view. But it does happen twice a year, when the orbits all align.
The picture above is from late March 2011, during one of these eclipse seasons. The edge of the Earth cut right across the disk of the Sun, creating this odd view. This particular shot is in the ultraviolet, where Earth's atmosphere is almost opaque, completely cutting off the Sun's light... except for that one little curlicue on the left. That's an extremely bright filament of material, luminous enough to have some of its light get through, despite our atmosphere.
This is a weird and wonderful picture, accessible only from space, which is why I picked it for this year's list. Image credit: NASA/GSFC/SDOOriginal imageOriginal blog post