NASA's Messenger spacecraft, which has been orbiting Mercury since March 18, is delivering key data points about the planet, its surface and particles in the atmosphere.
In a news conference, NASA highlighted some of the early data from the Messenger, which is sending back detailed images. Previous flyby images were low resolution. Messenger will orbit Mercury for three years.
Messenger revealed that there are "bursts of energetic particles" in Mercury's atmosphere due to the collision between the planet's magnetic field and solar winds. Messenger lead investigator Sean Solomon said the details about Mercury are recasting original ideas about how the planet functioned.
To be sure, there are many remaining mysteries about Mercury. For instance, Messenger sent back images of bright deposits on crater floors. These pits range from several hundred feet to miles wide. Researchers don't know what these pits represent, but "may suggest a more abundant than expected volatile component in Mercury's crust."
Messenger also discovered that Mercury has a lot of sulfur on its surface and that may indicate more volcanic activity. Other efforts of Messenger revolve around trying to confirm that water ice or other ices exist on the poles of the planet. Three Mercury flybys in 1974 revealed polar regions.