New research shows that sediments in the river delta inside the Jezero crater on Mars have been forming over time. This, in turn, suggests that the river could contain life, the evidence of which should have been well preserved.
The wavy streaks visible from space show that rivers once flowed on the surface of Mars, but how long did it take? Scientists argue that it is enough to leave traces of existing life.
The researchers speculated that the Martian crater Jezero could be a good place to look for signs of life. New analysis of satellite imagery confirms this hypothesis. By simulating the length of time it took to form layers of sediment in the delta deposited by an ancient river, the researchers concluded that if life had ever existed on the surface of Mars, traces of it could have remained in the delta sediments.
“Mars probably had water for a significant period of time, and the environment was certainly habitable even if it was arid,” says lead author Mathieu Lapotre. "We learned that sediment deposited quickly and that if organic matter was there, it would be quickly" mothballed."
Jezero Crater was chosen for NASA's next rover mission, in part because it contains a river delta known to effectively store organic molecules associated with life on Earth. New work by scientists offers guidance on how to extract samples to better understand the ancient Martian climate and the duration of delta formation.
Findings from the crater could also help to understand how life developed on Earth. If life once existed on Mars, then it most likely did not develop beyond the single-celled stage, scientists say. Its evolution was stopped by some unknown event that sterilized the planet. This means that the Martian crater can serve as a kind of time capsule that retains signs of life.