NASA Curiosity rover found evidence that the meteors found in Earth have originated from neighbor planet Mars.
The new study used a measurement called Sample Analysis at Mars (SAM). It revealed two types of the argon chemical element: the lighter and heavier types.
These chemical elements are common in the Solar System. Mars, however, provides an interesting case: the distinctions between lighter and heavier forms are distorted because Mars’ original atmosphere was already lost in space.
Argon, among the all the gases in the Red Planet, only has a small percentage left in its atmosphere. However since it doesn’t undergo any reactive changes with other chemicals or elements, it is an appropriate substance to trace the history of Mars’ atmosphere.
Earlier studies on the gases in the meteorites on Mars have already determined that the argon ratio in the Red Planet ranges from 3.6 to 4.5. With the SAM instrument, the researchers were able to confirm that the ratio of argon at 4.2.
According to Sushil Atreya of the University of Michigan, the ratio of argon would have been similar to those of Jupiter and the Sun if Mars was able to keep its original argon. The other two celestial bodies have very high gravitational forces that isotopes like argon cannot drift from them.
“Other isotopes measured by SAM on Curiosity also support the loss of atmosphere, but none so directly as argon. Argon is the clearest signature of atmospheric loss because it’s chemically inert and does not interact or exchange with the Martian surface or the interior. This was a key measurement that we wanted to carry out on SAM,” Atreya wrote in the report.
Determining the planet’s atmospheric loss would enable scientists to better understand how Mars transformed from a once water-rich planet to the drier, colder and less habitable one that it is today.
“We really nailed it. This direct reading from Mars settles the case with all Martian meteorites,” Atreya and her colleague Ann Arbor commented.
The study was published in the Oct. 16 issue of the Geophysical Research Letters.
