Hard to spot against the twilight glow near planet Earth's horizon, a crescent Mercury was imaged close up by the MESSENGER spacecraft early last week. Colors in this remarkable picture were created using data recorded through infrared, red, and violet filters.

Two days ago, the MESSENGER spacecraft became only the second in human history to swoop past Mercury. The last spacecraft to visit the Sun's closest planet was Mariner 10 over 35 years ago. Mariner 10 was not able to photograph Mercury's entire surface, and the images it did send back raised many questions.