NASA's Curiosity rover on Mars has found evidence confirming some meteors found on Earth did in fact come from the Red Planet, scientists report.

A key new measurement of Mars' atmosphere by the rover provides the most definitive evidence yet of Mars as the origin of many meteorites that have landed on the Earth, they said.

A high-precision count of two forms of argon gas -- Argon-36 and Argon-38 -- by the Sample Analysis at Mars instrument on Curiosity yielded figures matching analyses by Earth-bound scientists of gas bubbles trapped inside meteorites, the researchers said.

While these lighter and heavier forms, or isotopes, of argon exist naturally throughout the solar system, on Mars the ratio of light to heavy argon is skewed because much of the planet's original atmosphere was lost to space, leaving what's left relatively enriched in the heavier Argon-38.

"We really nailed it," lead study author Sushil Atreya of the University of Michigan said of Curiosity results, published in Geophysical Research Letters, a journal of the American Geophysical Union.

"This direct reading from Mars settles the case with all Martian meteorites," he said.