New evidence carried by NASA's Mars rover, Curiosity, shed light on the possibility that the now scorched Red Planet once has reliable waterways.
Photos of round and smooth pebbles that were sent by the rover three years ago strongly convinced scientists that these are concrete indications that three billion years ago a riverbed existed and might have washed and eroded these rocks.
"Thousand of years ago, Aristotle pondered the question of pebbles on the beach and how they become rounded... But until recently, descriptions of pebble shape have been qualitative, and we lacked a basic understanding of the rounding process," said a geophysicist from the University of Pennsylvania, Douglas Jerolmack.
Jerolmack and Gábor Domokos, a mathematician at Budapest University of Technology and Economics, and colleagues reported in Nature Communications that a rough estimate of 30 miles from the source can shape river pebbles. With this, a further conclusion can be drawn that a considerable river system that could support life really existed on Mars. "Knowing whether pebbles in a river moved 1 kilometer or 100 kilometers [0.6 miles or 62 miles] could tell us how stable water was on the surface of ancient Mars," Jerolmack said.
The team invented a tool to estimate how erosion can change the shapes of the rock. In theory, when rocks are washed in the river, its shape evolves as they are rubbed and collided against each other; thus, they will eventually become lighter, smoother and rounder. Here, the researchers would also like to determine the mass lost by the pebbles because of attrition. The team tested the tool in various places at different conditions.
Domokos revealed that "An object's shape can itself tell you a lot... If you go to the beach, natural history is written underneath your feet. We started to understand that there is a code that you can read to begin to understand that history."
