A new study has revealed that images from Mars show how water shaped the planet's landscapes billions of years ago. These images provide clues to help in the hunt for evidence of ancient life.
In February, the Nasas Perseverance Rover landed in Jezero Crater. Scientists believe that a long-gone river once nourished a lake. The sediment was found in a delta-shaped fan visible from space.
Science analysed high resolution images taken by Perseverance from the cliffs that once formed the banks of the Delta. The formation of the delta is revealed by layers within the cliffs.
Amy Williams, an astrobiologist at Nasa, and her Florida team discovered similarities between the features of the cliffs as seen from the crater floor (and patterns in Earth's river deltas). According to the study, the shape of the three bottom layers indicated that water was present and continued to flow early on. This suggests that Mars was warm enough to support a hydrologic period about 3.7bn year ago.
The top and latest layers contain boulders more than a metre wide scattered around, likely caused by flooding.
It is the fine-grained sediment in the base layer that should be sampled for signs of long-extinct living things if they exist on Mars.
These findings will aid researchers in determining where to send the Rover for soil and rocks which may contain biosignatures of Martian life.
Williams stated that we knew from orbital images that it was water that created the delta. These images are like reading a book, not just the cover.
Perseverence's main goal is to determine whether life could have existed on Mars. This project has taken decades to complete and has cost billions.
The multitasking rover will collect 30 soil and rock samples over the course of many years. These tubes will be sealed to allow for future lab analysis.
Perseverance scientists reported last month that Perseverance had gathered two rock samples from Jezero, showing signs of contact with groundwater over a prolonged period. They believe that the samples may have once been home to ancient microbial life. Evidence of this could have been captured by salt minerals.
Williams stated that discovering that Mars may once have been home to life would be one the greatest discoveries humanity has ever made.
She expressed her wonder at being able to see an ancient river system from another planet. It's eye-opening to be able to see something that no one else has seen before, she stated.
