Rare Meteorites Found on Earth are from Mars, Curiosity Rover Confirms

Image: NASA

Some meteorites that drop in on Earth come from Mars.
We have suspected this for years, but this week, NASA's Curiosity rover confirmed their origin.


Using Sample Analysis at Mars (SAM) instrument — a highly sophisticated onboard chemistry lab that can conduct hundreds of the same experiments we do on Earth — Curiosity rover found two forms of argon, a noble gas that doesn't react to other compounds. This is an important gas because it tells the straightforward history of Mars, which was once a wet planet similar to Earth.
While argon exists throughout our solar system, on Mars, the ratio of heavy to light argon is skewed due to the loss of its atmosphere over billions of years. This fundamentally changed it into the cold, desert-like planet that exists today.


Modern Mars is filled with the heavy form, Argon 38. The lighter form, Argon 36, rose to the top where it then easily escaped. In a sense, Curiosity uncovered the planet's hidden signature by pinning down the ratio of these two forms at 4:2. To put that into context, NASA's Viking landers estimated the planet's atmospheric value to be in the range of 4:7.


"We really nailed it," said lead study author Sushil Atreya of the University of Michigan, Ann Arbor, who published the work in the journal Geophysical Research Letters. "This direct reading from Mars settles the case with all Martian meteorites," he said.br />

Out of the tens of thousands of known meteorites to slam into Earth, less than 50 have been identified with Mars origins.


The study appears in Geophysical Research Letters, a journal of the American Geophysical Union.

NASA’s Mars Rover Curiosity begins extended exploration on trip to Mount Sharp

NASA’s rover Curiosity begins extended exploration on Mars

NASA's Mars Curiosity rover is beginning a long-awaited, 5-mile-long journey across the terrain of the red planet to begin exploring a rocky area known as Mount Sharp, 11 months after the rover arrived on the planet's surface, according to NASA's Jet Propulsion Laboratory. “With drives on July 4 and July 7, NASA's Mars rover Curiosity has departed its last science target in the 'Glenelg' area and commenced a many-month overland journey to the base of the mission's main destination, Mount Sharp,” NASA reported in a July 8 announcement.

Curiosity has already checked off its main mission goal, finding that a site called Yellowknife Bay was indeed habitable billions of years ago. The car-size rover — which is nuclear- rather than solar-powered — has embarked on a months-long trek to the base of a 3.4-mile-high (5.5 km) mountain called Mount Sharp.

NASA's long-lived Opportunity Mars rover has reached the site where it will wait out its sixth Red Planet winter.

Opportunity — which touched down on Mars in January 2004 just after its twin, Spirit, arrived on the planet — is studying rocks at the foot of a location called Solander Point, whose north-facing slope will allow the robot to tilt its solar panels toward the sun during the coming southern Martian winter.

"We made it," Opportunity project scientist Matt Golombek, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement. "The drives went well, and Opportunity is right next to Solander Point. We know we could be on that north-facing slope with a one-day drive, but we don't need to go there yet.

The days are getting shorter in Mars' southern hemisphere, and the amount of sunlight available to the solar-powered Opportunity will reach a minimum in mid-February 2014 (the southern winter solstice occurs on Feb. 14).