NASA’s Messenger spacecraft flew by Mercury in 2008 and 2009. In March 2011, it began to orbit Mercury. Messenger will study parts of Mercury that have not been seen before—letting scientists learn many new things about the planet. Mercury’s eccentric orbit takes it as close as 47 million km (29 million miles) from the sun. If one could stand on the scorching surface of Mercury when it is at its closest point to the sun, the sun would appear more than three times as large as it does when viewed from Earth.