The Curiosity Rover recently discovered that meteorites that drop on Earth sometimes come from Mars.

NASA's Curiosity Rover has finally confirmed what scientists have long suspected: the  Martian origins of meteorites that fall on Earth.

"We really nailed it," said Sushil Atreya,  the lead author of a paper reporting the finding, in a press release. "This direct reading from Mars settles the case with all Martian meteorites."

Using the Curiosity's Sample Analysis at Mars (SAM) instrument, scientists confirmed two forms of argon on Mars that narrate the history of the planet.

While argon, a noble gas, is found throughout the solar system, it reveals the history of Mars as it transitioned from a wet planet, like Earth, to a dry planet thanks to the loss of atmosphere. The ratios of heavy argon and light argon are skewed on Mars, because the atmosphere is literally disappearing.

Mashable explains,

"Modern Mars is filled with the heavy form, Argon 38. The lighter form, Argon 36, rose to the top where it then easily escaped. In a sense, Curiosity uncovered the planet's hidden signature by pinning down the ratio of these two forms at 4:2. To put that into context, NASA's Viking landers estimated the planet's atmospheric value to be in the range of 4:7."

While thousands of meteorites have found their way to Earth, less than half have been suspected as coming from Mars.

Now, however, we know definitively that they did.

The new study will appears in Geophysical Research Letters, a journal of the American Geophysical Union.