Laser-zapping of a globular, golf-ball-size object on Mars by NASA’s Curiosity rover confirms that it is an iron-nickel meteorite fallen from the Red Planet’s sky.
Iron-nickel meteorites are a common class of space rocks found on Earth, and previous examples have been seen on Mars, but this one, called “Egg Rock,” is the first on Mars examined with a laser-firing spectrometer. To do so, the rover team used Curiosity’s Chemistry and Camera (ChemCam) instrument.
Scientists of the Mars Science Laboratory (MSL) project, which operates the rover, first noticed the odd-looking rock in images taken by Curiosity’s Mast Camera (Mastcam) at a site the rover reached by an Oct. 27 drive.
ChemCam found iron, nickel and phosphorus, plus lesser ingredients, in concentrations still being determined through analysis of the spectrum of light produced from dozens of laser pulses at nine spots on the object. The enrichment in both nickel and phosphorus at some of the same points suggests the presence of an iron-nickel-phosphide mineral that is rare except in iron-nickel meteorites, Meslin said.
Iron meteorites typically originate as core material of asteroids that melt, allowing the molten metal fraction of the asteroid’s composition to sink to the center and form a core.