Two satellites peering at the sun have snapped photos of Mercury's long, comet-like tail, but it took an amateur astronomer to bring the pictures to light.
The twin satellites are part of NASA's Stereo (Solar Terrestrial Relations Observatory) mission. They zip around the sun in Earth's orbit, one behind our planet and one ahead of it. Their main job is to monitor the sun and its atmosphere.
Since Mercury is so close to the sun, the planet occasionally wanders into the satellites' photos. Some of these images show a long, comet-like tail streaming off the planet, away from the sun. [ New photo of Mercury tail.]
Astronomers didn't notice the tail in the photos right away. But it didn't escape the eyes of Australian medical researcher Ian Musgrave.
Musgrave was poring over an Internet database of