Life seems to be a big fan of two things: sunshine and water. (Really, though, have you hydrated lately?) This is the exact reason NASA targeted the Jezero Crater on Mars for its Perseverance rover’s landing site; scientists believe the crater was home to a huge lake billions of years ago, which may itself have hosted life. Now, new evidence beamed back to Earth by Perseverance confirms the past existence of a lake beyond a shadow of a doubt. And the discovery makes the detection of extinct life seem tantalizingly close.
Gizmodo picked up on the new evidence, which comes in the form of detailed images of long, steep slopes in the crater. These slopes—which scientists refer to as escarpments—formed from sediment accumulating at the mouth of an ancient river. One that project scientists can now confirm fed a lake the size of Lake Tahoe.
“Never before has such well-preserved stratigraphy [of the escarpments] been visible on Mars,” Nicolas Mangold, a Perseverance scientist from the Laboratoire de Planétologie et Géodynamique in Nantes, France, said in a NASA press release. Mangold, lead author of the paper outlining the escarpment images in the journal Science, added that “This is the key observation that enables us to once and for all confirm the presence of a lake and river delta at Jezero.”
By studying the stratigraphy of the escarpments—that is, the sedimentary layers of the slopes that reflect environmental changes on geological timescales—Mangold and his colleagues were able to observe that the crater’s river delta has horizontal layering very similar to what a geologist would expect to see in a river delta on Earth. The scientists also studied the stratigraphy of a rock outcropping in the former lake. The outcropping, “Kodiak,” had the same layering.
Mangold said in NASA’s release that within the layers there were boulders that “had no business” being inside of the crater; a sign that water must’ve carried them there. In fact, the scientists believe that flash floods carried the giant stones. Ones that could’ve carried the rocks for tens of miles and sped along at 20 mph.
These findings will now impact from which location NASA will send back sample rocks to Earth. Something that will hopefully happen by 2031. If that mission is successful, scientists will be able to study Martian dirt back here on terra firma. And look much, much closer to see if there are any tiny signs of extinct life.