This is an awesome picture. Supercell Thunderstorm by Sean Heavey, nationalgeographic: A supercell thunderstorm rolls across the Montana prairie at sunset. This was a winning shot in the 2010 National Geographic Nature Gallery Photo Contest.
Butterfly Nebula - gas released by a dying star racing across space at more than miles an hour, forming the delicate shape of a celestial butterfly. Also known as NGC 6302 or the Bug Nebula. Credit: NASA, ESA, and the Hubble ERO Team