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NASA’s Messenger Spacecraft Discovers Surprises on Mercury
By Kenneth Chang, Published: July 19, 2010
- NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Flyby finds Volcanic deposits were identified in the double-ring Rachmaninoff crater.
On its third swing past Mercury, NASA’s Mercury Messenger spacecraft discovered an unexpectedly young lava plain, rapid rufflings of the planet’s weak magnetic field and an unanticipated dance of elements in the thin atmosphere.
“I think the biggest surprise for the community is that the planet is turning out to be much more dynamic than people appreciated,” said Sean C. Solomon of the Carnegie Institution of Washington who is the principal investigator for the Messenger mission.
.In Mercury Images, Remarkable Features in a Crater >
Messenger.jhuapl.edu
Where the lava flowed Images from the Messenger show smooth plains that indicate the importance of volcanism in Mercury’s past.
The flyby occurred in September, when the spacecraft
swooped within 142 miles of Mercury’s surface at 12,000 miles per hour, but the findings of that flyby just appeared in three papers the journal Science published last week on its Web site. Within the 180-mile-wide double-ring Rachmaninoff crater, Messenger photographed flat, smooth plains that scientists interpreted as the hardened outflow of lava.
Based on the number of smaller impact craters, the age of the volcanic deposits within Rachmaninoff is probably less than two billion years, said Louise K. Procktor of the
Johns Hopkins University Applied Physics Laboratory and lead author of
the paper that examined the crater. While not recent, that would still suggest that Mercury was volcanically active well into its middle age, given that it formed 4.5 billion years ago with the rest of the solar system. “It is quite a big surprise,” Dr. Procktor said.
Read more...
.Mercury Topics and Slideshows
Past Coverage:
Messenger Spacecraft to Photograph Mercury (September 28, 2009)
In Mercury Images, Remarkable Features in a Crater (May 5, 2009)
Flyby of Mercury Answers Some Old Questions (July 8, 2008)
Pictures Reveal Mercury's Tumultuous Past (January 31, 2008)
