Claims of water being present on Mars have existed since 1870 with the first quantities of water actually being detected in 2003 by the Mars Odyssey spacecraft.
Now, according to an article published yesterday in the journal Geology, there is evidence that Mars is home to vast reservoirs of water in its interior as well. The utility of this evidence comes in the prospects of extraterrestrial life (no, not full fledged aliens) and future human colonisation.
The research itself did not require any samples from Mars; rather, by analysing the water content of two meteorites ejected roughly 2.5 million years ago, they were able to determine that Mars has somewhere between 70 to 300 parts per million of water in the mantle - a figure that is not too far from that of Earth’s 50 to 300 parts per million.
If all of this can be deduced from two meteorites that crashed on Earth over a century back, only time will tell what future missions to Mars could yield.