According to a recent study, Martian pebbles identified by NASA’s Curiosity rover suggest that the Red Planet once had flowing rivers.
These findings, published in the journal Nature Communications, resulted from research conducted by experts at the University of Pennsylvania and Budapest University of Technology and Economics.
An analysis was performed, which initially focused on photographs taken by NASA’s car-sized robotic rover which completed a successful Mars landing on August 6, 2012.
At the time, Curiosity surveyed Aeolis Palus, a plain located between the 93-mile wide Gale Crater and Mount Sharp. This is how rounded pieces of rock were discovered by the rover, and recent experiments indicate that these stones are extremely similar to those found in riverbanks from our planet.
At first, NASA had estimated that the Martian pebbles had come from tiny creeks. However, the study authors seem to suggest that in fact they originated from larger bodies of water, whose strong flow contributed to their final morphology.
Basically, this new theory states that the rocks were carried across miles, by the strong water current. As they rolled and bounced on the waves, their shape was progressively chiseled, until it lost its initial angular structure.
In order to demonstrate this hypothesis, mathematician Gabor Domoskos carried out an experiment to see how long it would take for a “blocky rock” to become rounded and smooth.
He showed that when two particles of roughly the same size hit against one another, they affect each other’s shape, whichever their material and environment might be.
This was supported by a lab experiment where limestone rocks were placed inside a rolling drum. Measurements were taken, as the fragments changed their shape and mass, and the predictions made by the computer model were proven accurate.
Afterwards, researchers analyzed rock shapes pertaining to a river in Puerto Rico, starting at the headwaters and moving downstream. It was determined that blocks of stone eventually became increasingly more circular as they flipped and tumbled down the fast stream.
Another test was conducted at the mouth of a canyon in New Mexico, and once again it was proven that there is a clear association between the pebble’s rounded morphology and the distance they had to travel across the water.
Based on these findings, the researchers assessed how long Martian rivers would’ve had to be, so that the photographed stones would acquire their distinct shape.
While taking into account gravitational forces (which are 62% lower than those on Earth) it was determined that the pebbles lost 20% of their volume and must have journeyed over 30 miles (50 kilometers) in order to achieve their current appearance.
The findings therefore seem to indicate that Mars must have had an intricate river system, which suggests it must have also been capable of supporting life.
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