A study of an ancient Martian meteorite found in Morocco in 2011 suggests that Mars was once a warmer place with much more water, scientists who analyzed the rock announced Thursday.
The meteorite, dubbed NWA7034, is believed to be a more than two-billion-year-old piece of Martian crust containing more water than any previous Martian meteorite ever found on Earth.
"This is a new type of meteorite—the best match we have is with the soil that the Mars rovers are currently measuring," says Carl Agee, a meteorite curator at the University of New Mexico. "It has 10 times as much water in it than the most watery meteorites we've found until now."
According to Agee, that means Mars may not have always been as seemingly desolate as it is now.
"We know Mars as a cold, dry desert planet with a thin atmosphere," he says. "This suggests early Mars was warmer, wetter, and a possible harbor for life. Sometime between when this meteorite was formed and what we have now, there was a climate change."
(Courtesy of Carl Agee)
So far, there have been about 100 Martian meteorites discovered on Earth—propelled here through space by some sort of explosion or asteroid impact. Most fall into two groups: Shergottites and Nakhlites. Both groups are believed to be less than a billion years old and contain relatively little water. Agee says it took more than a year to determine that NWA7034 was from Mars, because it is unlike anything scientists have seen before.
"If it had been a garden variety of a type that's already well known, I could spend a few hours in the lab and tell you it's from Mars," he says. "For this, we had to assemble a new array of data to build the case for it being from Mars, to form a coherent story. But it looks like what the Mars rovers are seeing in terms of geochemistry."
That might mean it's from Mars's surface layer, while other meteorites could have come from deep within craters, Agee says. He and his team are currently working on a study to determine how long the meteorite was traveling in space before it impacted Earth. So far, the team has not found microfossils to prove Martian life on the meteorite.
Despite the find, Agee says it's still important to obtain a current sample from Mars's surface in order to continue the search for microbes on the planet.
"There's still the question of exactly where on Mars this came from," he says. "This doesn't replace sample return, but it's certainly complimentary to our rover activities."