Images of Mars reveal how water helped shape the landscape of the Red Planet billions of years ago and provide clues that will guide the search for evidence of ancient life, a new study finds.
In February, NASA’s Perseverance rover landed in Jezero Crater, where scientists suspected a missing river once fed a lake, depositing sediment in a fan-shaped delta visible from space.
The Science study analyzed high-resolution images captured by Perseverance of the cliffs that were once the shores of the delta. The layers inside the cliffs reveal how its formation took place.
NASA astrobiologist Amy Williams and her team in Florida have discovered similarities between the features of the cliffs seen from the crater floor and the patterns of the Earth’s river deltas. The shape of the three lower layers showed a constant presence and flow of water early on, indicating that Mars was “hot and humid enough to support a hydrological cycle” around 3.7 billion years ago, according to the ‘study.
The upper and more recent layers present blocks of more than a meter in diameter scattered, probably washed there by violent floods.
But it’s the fine-grained sediment in the base layer that will likely be the target of sampling for signs of long-extinct life – if it existed – on Mars.
The results will help researchers determine where to send the rover for soil and rocks that may contain valuable “biosignatures” of putative Martian life forms.
“From the orbital images, we knew it must be water that formed the delta,” Williams said. “But having these pictures is like reading a book instead of just looking at the cover. “
Finding out if life could have existed on Mars is the main mission of Perseverance, a project that took decades and cost billions of dollars to develop.
Over the course of several years, the multitasking rover will collect 30 rock and soil samples in sealed tubes, which will eventually be sent back to Earth in the 2030s for laboratory analysis.
Last month, mission scientists announced that Perseverance had collected two rock samples in Jezero that showed signs that they had been in contact with groundwater for a long time. Their hope is that the samples may, at some point, have harbored ancient microbial life, evidence of which may have been trapped by saline minerals.
Learning that Mars may once have been home to life would be one of the most profound discoveries mankind has ever made, Williams said.
She also expressed her wonder at having a window into an ancient river system on another planet. “It’s really eye-opening to see something that no one on Earth has seen before,” she said.