Mercury's magnetic field is "alive." Volcanic vents ring the planet's giant Caloris basin while the planet itself is surrounded by a plasma nebula of surprising complexity. These are just a few of the new discoveries made by NASA's MESSENGER spacecraft and reported in a special July 4th issue of Science magazine.
FULL STORY at
http://science.nasa.gov/headlines/y2008/03jul_mercuryupdate.htm?list1052465
