A massive Martian meteorite - August 04, 2009
Posted for Mico Tatalovic
NASA’s Opportunity rover has discovered what appears to be the largest meteorite ever found on Mars. Dubbed ‘Block Island’ the rock measures 60 cm across (press release).
Opportunity first stumbled across the rock on 18 July, before snapping pictures to send to Earth and motoring calmly on. "The images came down after we had already passed," says planetary scientist Albert Yen of NASA's Jet Propulsion Laboratory in Pasadena, California (Space.com).
Scientists then instructed the rover, which was on its way to examine Endeavour Crater some 15km away, to backtrack and have a closer look.
Using its onboard spectrometer to assess the rock's chemical composition, Opportunity confirmed the rock was indeed a meteorite, probably a fragment of the rock responsible for blasting out the 800m wide Victoria Crater Opportunity had been exploring for a year until it climbed out last August.
Investigating such meteorites may help scientists better understand the asteroid belt, as well as providing clues about climate on Mars; signs of weathering, including rust, could provide important clues to the presence of liquid water. Using the size of the meteorite in models could also shine light on the Red Planet’s atmosphere at the time of the impact.
"We didn't drive Opportunity to Endeavour Crater to find meteorites, but we found one that's pretty darn big," Ray Arvidson, a member of the rover team from the Washington University in St. Louis, Missouri told New Scientist. "It might tell us more about the meteorite, and more importantly, it might tell us more about Mars."
Image: close up image of "Block Island" taken on July 28 / NASA/JPL-Caltech
