NASA’s Curiosity rover proved that Mars sometimes throws meteorites at us. The SUV-sized robot used its Sample Analysis at Mars (SAM) instrument to make the connection.
Scientists have long suspected that some meteorites that fall to Earth came from our neighboring planet. However, they haven’t been able to prove it.
The rare meteorites contain a similar ratio of argon-36 to argon-38 that Curiosity found in Mars’ atmosphere, reports CBS News. Using SAM, the rover found a ratio of 4.2 to 1, while an earlier analysis of the suspected Martian meteorites found a ratio of 3.6-4.4 to 1.
The findings were detailed in the journal Geophysical Research Letters on Wednesday. In a press release, study lead author, Sushil Atreya of the University of Michigan, Ann Arbor, explained, “We really nailed it. This direct reading from Mars settles the case with all Martian meteorites.”
So, while scientists suspected it for a long time, Curiosity was able to confirm that Mars sometimes pelts us with rocks. Still, the ratio of Martian meteorites is very small, notes Mashable. Of the tens of thousands of small rocks that crash into Earth, less than 150 are believed to have come from Mars.
Along with determining the origin of meteorites, the argon ratio allows scientists a better picture of Mars’ early atmosphere and how much has been lost over the last several billion years. Understanding the loss can help them know how the Red Planet changed from a wet and warm climate into a dry and cold world.
Argon is an important chemical, because it doesn’t react with other compounds. It allows scientists to better understand Mars’ history. The chemical exists throughout the solar system, but the ratio on Mars is skewed because of its atmosphere loss. The lighter argon-36 escapes, leaving behind the heavier argon-38.
Earlier measurements from Curiosity showed that there isn’t any methane on Mars. The rover also found that water once flowed freely across the planet’s rocky surface. Curiosity is on its way to Mount Sharp, in the middle of the Gale Crater, to discover more of Mars’ history.
[Image by NASA/JPL via Wikimedia Commons]