Sean Solomon, director of Columbia University's Lamont-Doherty Earth Observatory, has been leading NASA’s MESSENGER mission to Mercury for the last four years. MESSENGER is the first spacecraft to orbit Mercury. Now as it is expected to come crashing down on the second closest planet to the sun, the mission is coming to a close. But Solomon believes MESSENGER has given us significant data from mapping Mercury’s surface and delving into the planet’s origins, atmosphere, magnetic field and interior. It may even have given us clues into how Earth formed and evolved.