With the Messenger spacecrafts recent September flyby of Mercury in “safe mode” due to some power issues there was a concern that it wouldn’t have been as useful a scientific opportunity as originally hoped. Indeed it only collected about half of the data it was hoping to.  We do however have nearly a 100% detailed map of the surface. With this new data came a surprise for the the geologist.

Credit Nasa: Physics Lab - Note this is artifically coloured....

The data has revealed much higher concentration of iron bound up in oxides with titanium on the surface than previously known. We’ve known the planet probably had an iron core due to it’s high density but have only detected low amount on the surface. Estimates but the planet at about 60% Iron.

Sean Solomon, the mission’s principal investigator, said the new observations would keep theoreticians busy in a recent statement to reporters.

“The iron is in a form that we don’t normally encounter in other planetary situations and so it’s going be a volley back to our geochemists and petrologists to come up with a scenario that’s consistent with everything we are measuring now at Mercury”

One theory is that what we see is the core of a once larger planet which had the outer layer blasted away in a collision early in its life.  I’ll leave the final conclusion to the experts and wait for more data in 2011.

If you haven’t been following the Messenger mission then the idea was for the craft to eventually go into orbit around the planet in about 2011. This 3rd and final flyby was to perform a gravitational braking maneuver to allow that final orbit insertion. So from that perspective the flyby was successful and we also got to see more of the planet close up that had been seen previously. I’ve mentioned in a previous blog and posted one of the new composite images.