The persistent rover, which spent months traveling to Mars, could not have landed at a more interesting location.
Jezero Crater — an area of dry, windswept Martian rock where the rover landed in February — was once a lake bed fed by an ancient river whose flood was so powerful that it could move the rocks, scientists say.
These findings, published last week in Science, confirm scientists’ suspicions that the crater contained a lake millions of years ago, and also suggest that this part of Mars had a hot, humid past with a more complex water cycle than is known.
“There were noisy rivers here,” said Katie Stack Morgan, Mars 2020 Project Scientist and author of the article, of Jezero’s landscape about 3.5 million years ago. “Jezero would have been a great place to live and that environment has changed over time.”
More studies could help researchers understand why the planet is drying up and provide new clues about whether the planet ever supported life.
View from the ground
A new perspective – through perseverance – and the scientists’ geological investigation work made this information possible.
The rover, which transmitted images of the surface of the crater to Earth, provided scientists with new views that cannot be seen from space.
“What you think you see from orbit around Mars may not be what you see when you enter a crater at eye level,” Stack Morgan said.
Surface-level images supported the scientists’ theory that Jezero once contained a deep lake.
The images also gave scientists, including the 39 authors of the science article, the ability to analyze the layers of rock on an outcrop called the Kodiak. The researchers found that these layers match the way river deltas appeared on Earth, indicating the flow of water into the ancient lake.
But the visuals also contained some surprises. On other cliffs near Kodiak, scientists noticed large boulders — some up to five feet in diameter and shaped by water — in the upper layers of the formations, according to a science article.
They suspect that the rocks were deposited during flash floods strong enough to quickly transform Martian watersheds.
They don’t know the cause of the flood, but they speculated in the document that heavy rainfall, rapid snow melt or changes in glacial ice could have triggered the floodwaters.
“It can be very difficult to rebuild this kind of thing,” Stack Morgan said.
Searching for signs of life
Perseverance is the first rover to collect and store Martian rock samples.
Stack Morgan said it’s exciting to know for sure that the rover will visit and collect samples from an ancient lake fed by rivers.
This means that the rover will have access to a variety of rock types that were deposited in the crater. The rover should also be able to reach and sample parts of ancient lake beds, she said, which are “exactly the kind of beds out there on Earth that are great for organic matter and bio-fingerprints.”
The rover may be in the right place to answer some of humanity’s deepest questions.
“That’s why we came to Jezero with such perseverance,” she said. “So far, Jezero has not disappointed”.