NASA’s Curiosity rover just happened upon a meteorite. It’s a beauty, too. While poking around the bedrock of “Somesville” in the Murray Formation on Mars last Friday (Oct. 28), Curiosity’s color camera snapped a photo that included a small, shiny metallic meteorite. It’s about 1.6 inches (4 cm) across with an ovoid shape, hence its nickname “Egg Rock”.
Two sols later on October 30, the rover took two closeups of the meteorite and performed a chemical analysis using its ChemCan Remote Micro-Imager. Verdict: it’s composed of metal, no doubt a mix of iron and nickel, which are the metals commonly found in metallic meteorites that fall to Earth. The lustrous, melted surface is striking and indicates that the space rock was partially melted during its high-speed passage through the Martian atmosphere.
And those lovely holes, called regmaglypts, may once have housed softer, more easily stripped away minerals that vacated the meteorite in the heat and pressure of its plunge through the Martian air. If this were Earth, the smooth, shiny texture would indicate a relatively recent fall, but who’s to say how long it’s been sitting on Mars. Mars is not without erosion from wind and temperature changes, but it lacks the oxygen and water in the air and on the ground that would really eat into a rock like this.
What I find interesting is that despite Mars’ thin air (the pressure is less than 1% of Earth’s atmosphere at sea level), there’s enough atmosphere to heat and melt a metallic asteroid fragment. This isn’t the first meteorite discovered on the Red Planet. NASA’s Opportunity rover found five metal meteorites and Curiosity’s rumbled by its first find, a honking big hunk of metallic gorgeousness named Lebanon, in May 2014.
Mars is currently in the evening sky and visible as a bright, reddish “star” in the southwest well to the left of the moon this evening, but the real action is further west towards the crescent moon. Watch this evening (Nov. 2) starting about 45 minutes after sunset, when the moon pairs up with two planets: brilliant Venus and fainter Saturn. They’ll form a pretty trio in the southwestern sky. For more about this conjunction, please my article in Universe Today.