A rover on Mars is uncovering ancient signs of flowing water. That could mean it once had life
Recent findings like this image show a river used to pass through a region of Mars.
In a dried up lake on the surface of Mars, there is a giant rock and multiple rocky remnants that look like a place on Earth. Once thought to be a barren rocky planet, recent findings like this image at Jezero crater are uncovering evidence that a river used to pass through a region on the red planet.
Maybe Earth is not so different from other planets after all.
“[There’s] this gorgeous little mound of rocks that has the most exquisite patterns in it,” says Dr. Amy Williams, an astrobiologist at the University of Florida. “It tells us about the history of the flow of water in the Jezero crater on Mars.”
Thanks to NASA’s Perseverance Rover, scientists are able to see this rock for from the surface of the planet the first time — a first glimpse of the rocky remnants of an ancient river that flowed on Mars billions of years ago. Perseverance touched down in Jezero crater, an ancient riverbed that once flowed with liquid water.
Scientists believe this formation at Kodiak is a remnant, the leftover stuff as the ancient delta at Jezero crater eroded away. It could have been a great place to have a nice little lake and could have been a really pleasant environment except for the fact that humans need to breathe oxygen.
Luckily, Perseverance doesn’t need oxygen.
“You can almost picture an earth-like environment where these kinds of dynamic processes are occurring,” said Wiliams. “But it was on Mars in the distant past.”
Findings from the rover show that there wasn’t just a river flowing, there was flooding. “We can understand the history of water flowing in Jezero crater,” she said. “It actually told us a bit about these flooding events that have occurred in the crater as well.”
Williams expected to see layers consistent with a delta in the lake like what they saw at Kodiak, but they did not expect to see boulders. So how did they get there? One idea is that there could have been flooding events that brought down these huge boulders.
The presence of these boulders give scientists clues about the climate on Mars, the flow of water and how fast it might have been. Before Perseverance, Williams’ team relied on orbital images — pictures of the surface taken from high above the planet. But with a rover on the ground, her team spotted the boulders — further evidence there was once a dynamic river that flowed and flooded over the course of ancient Martian history.
The findings bring scientists one step closer to getting a sense of what some places beyond earth used to look like. It’s “the power of geology,” says Williams.
Searching for signs of ancient life
As an astrobiologist, Williams is not only looking to explore the history of Maritan rivers, she’s also looking for signs of tiny microorganisms from plants and animals. Because acneicent Mars contained liquid water, scientists say there’s a good chance it could also contain past life.
“One of the environments that astrobiologists want to look at for the preservation of these types of biosignatures – or evidence for life – are in very fine-grained sediments deposited in lake beds,” says Williams. “When we see how this delta has flowed into the lake, how the sediments have deposited, that tells us about where those really small grains, sediments are also going to be deposited.”
Perseverance has the tools to help astrobiologists identify the best samples from Mars and to select the best ones to bring back to Earth. NASA plans to send another rover to the surface and collect these samples, then launch them back to Earth for scientists to examine closer.
“All of this information together can tell us the absolute best place to collect these samples,” says Williams.
These findings could provide compelling evidence for life beyond Earth and confirm scientists’ suspicions that Mars once had life.
“These are the things on Earth that we use to identify biosignatures like looking at organic carbon, looking at microfossils,” says Willaims. “Those are the tools that we’re trying to use to triage these samples for return to Earth.”
For Willaims, the findings at Kodiak in Mars’ Jezero crater are just the beginning and there are more places her team wants to visit.
“We’re actually going to drive up the Delta to collect samples to explore the environment more and understand a lot more about Mars’s history and the climate, all of that information is recorded in those rocks,” she says. “There’s a ton of great stuff on the way.”
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