Last Thursday, the Opportunity Rover on Mars took a photo of the landscape on its way to Endeavor Crater and turned up something interesting. Mission controllers spotted a curious rock about 18 inches across some 102 feet in the distance which they suspected to be a meteorite. “”The dark color, rounded texture and the way it is perched on the surface all make it look like an iron meteorite,” said science-team member Matt Golombek of NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
The rock has been given the informal name of “OileÃ¡n Ruaidh” (ay-lan ruah) or Red Island, the Gaelic name of an island off the northwestern coast of Ireland. It’s about the size of a crockpot. Since its discovery, scientists have directed the rover into position for a closer look.
Opportunity has found four iron meteorites during its 14.5 miles of travel since arriving on Mars in early 2004. Judging by appearance alone, this one is likely the 5th. Look at the dimpled texture and the torn edges along the deep fissure on the left side – all classic textures found in many meteorites but irons in particular. Yes, I think I would like to add this one to my collection. Which would be rarer I wonder – a meteorite found on Mars or a piece of Mars itself? Because the planet is closer to the asteroid belt than Earth, and the belt is where many of the meteorites on Earth come from, Mars gets pelted even more often by space rocks than we do. Combine that with an atmosphere nearly devoid of oxygen and water vapor and lots of open, desert-like landscape, and you’ve got the perfect place in the solar system to hunt for meteorites.
If scientists find iron and nickel in the rock with the rover’s x-ray spectrometer – telltale elements in many meteorites – they’ll clinch it.Â There’s something else curious about this rock. Red Island is sitting on the surface just as if someone picked it up and set it there. No impact mark, no hole. My hunch is that it fell so long ago that the erosive forces on the planet have completely stripped away the underlying sand and rock, leaving it all to itself. A hunk of iron would hold up much better to erosion by wind than softer rock. It’s also possible it was moved from its original location by a flash flood a couple billion years ago when Mars is postulated to have been a much wetter planet. All speculation I know, but check out what similar erosion processes have done in the North Dakota Badlands. I was there this summer and hiked into a small canyon along the Paddington Creek trail. There, eerie pedestals of clay held chunks of petrified trees 10 feet above the ground. The softer clay eroded much faster than the trees and rocks, leaving them perched in the air. The tougher wood and rocks also help shield the clay immediately beneath. The two processes worked in tandem to create the strange pillars. Eventually the clay will melt away entirely, and petrified wood and harder rocks will lie scattered about the ground. An analog to our possible meteorite?
To learn more about the new potential meteorite discovery, I encourage you to visit the Mars Rovers website and follow the excellent Road to Endeavour blog by Stu Atkinson. Stu has lots more photos, including several 3D versions, one of which I’ve posted. All you need is a pair of those red-blue glasses, and you’ll feel like your standing right next to Opportunity.