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Green meteorite may have rare cosmic origins

It’s a first for astronomers.

A newly discovered green meteorite, dubbed NWA 7325, may have arrived from the planet closest to the sun, according to scientists. Speaking earlier this week, astronomers say they now believe a rare greenish meteorite is the first ever discovered from Mercury. The green rock, discovered in Morocco last year, is under examination by a group of scientists at the University of Washington. The findings were presented during the 44th annual Lunar and Planetary Science Conference in The Woodlands, Texas.

The space rock, which scientists estimated to be around 4.56 billion years in age, is thought to have arrived on Earth after being blasted off the surface of Mercury. While the evidence collected by scientists seems to point to Mercury as the planet of origin, they hinted that it may have also come from an unknown body in the solar system.

“It might be a sample from Mercury, or it might be a sample from a body smaller than Mercury but [which] is like Mercury,” said meteorite scientist Anthony Irving, who is leading the study. “A large impact could have shot NWA 7325 out from Mercury to Earth.”

One thing is for certain: the meteorite is not a product of Mars. While it was collected along with a group of nearly 40 other meteorites that entered Earth’s atmosphere in 2012, this rock is the only one thought to have originated on a planet other than Mars. According to astronomers, meteorites originating on Mars are often easy to identify since most of them show evidence of passing through the Martian atmosphere.

Astronomers were able to identify the origins of the space rock by employing a bit of scientific sleuthing. NWA 7325 has a lower magnetic intensity — which originates as the rock passes through a planet’s magnetic field. Data collected by NASA’s Messenger spacecraft provided astronomers with the necessary data; Data collected by the spacecraft shows the planet’s low magnetism closely resembles that of  NWA 7325.

The rock is likely the result of Mercury’s early days as a planet. Recent evidence seems to suggest the planet began its life as a rocky bit of molten lava. Scientists at MIT say the planet likely harbored a large, roiling ocean of magma very early in its history, shortly after its formation about 4.5 billion years ago.  Evidence suggests that the meteorite formed as “scum” on the top of the magma, before being shot off into space, Irving said.

It remains unclear how much the space rock is worth. Martian space rocks are among the rarest materials on Earth and they often sell for around $11,000 to $22,500 an ounce. The Mercury space rock is likely priceless, simply for the fact it is the only one ever identified by astronomers. The collection of space rocks that fell in the desert of Morocco last year captured worldwide attention at the time. Astronomers, in the weeks that followed, confirmed that 15 pounds of meteorite from Mars fell, providing one of the largest collections of pristine space rocks ever collected.