After the Mars rover Perseverance successfully collected its first rock samples these days, initial analyses are providing NASA researchers with evidence that water has long existed on Mars. “It looks like our first rocks reveal a potentially sustainable habitable environment,” said Ken Farley, a geochemist involved in the mission.
Perserverance had collected samples Sept. 6 and Sept. 8 and sealed them in a container. Along with later rock samples, the samples will be picked up by another probe in a few years and brought back to Earth, when they can be analyzed in more detail to reconstruct volcanic activity and water resources, for example.
The Perseverance science team already knew that water had once filled the Jezeros impact crater from which the rock samples came; it was unclear until now how long. One conceivable possibility so far was that Jezeros Lake was formed by flooding and dried up within 50 years.
Now the researchers think they can interpret from the changes in the rock that groundwater was present for a long time. This groundwater could be related to the lake in the crater or it had seeped through the rocks long after the lake dried up. While NASA researchers still can’t say whether the water that altered these rocks was present for tens of thousands or millions of years, they are now more certain that it was present long enough to allow micro life.
The rocks in the samples are basaltic and may have come from lava flows. Crystalline minerals in it could help date when it formed. “Each sample may be part of a larger historical puzzle,” NASA writes. Put in the right order, it potentially yields a timeline of key events in the crater’s history, such as when it formed, when the lake formed and disappeared, and how the Martian climate changed, it says.