NASA scientists working at Mars Science Laboratory mission (MSL) now believe that they found how the 5.5-km high mountain at the center of the Gale Crater on Mars might have formed. They now think that this mountain (Mount Sharp) have been created during tens of millions of years by successive addition of sediment layers by the lakes that used to fill the large bowl.
Mount Sharp has been discovered by Curiosity, NASA’s robotic rover that has been exploring the Martian crater since late 2011. Researchers now say that if the hypothesis about Mount Sharp’s creation is true, this means Mars was a lot warmer and wetter than it is today. Mars might have had a rich hydrological system that involved cycles of snows and rains that filled the Red Planet with lakes, deltas and even an ocean.
Dr Ashwin Vasavada, chief scientist for Curiosity project, said that the planet needed a large body of water such an ocean to prevent a million-year-old Gale lake from evaporating.
Scientists first thought that the mountain inside Gale crater was formed after an asteroid or comet impacted Mars’ surface and the ground rebounded due to the collision, but this didn’t explain why the mountain was so high. The puzzle was solved when curiosity send back on Earth close-up images with the Gale crater and its mysterious mountain.
From Curiosity’s images, scientists noticed abundant layers of sediments that have been deposited by long-gone rivers. Researchers drew the conclusion that these rivers created deltas and permanent lakes at the crater’s center.
Curiosity also revealed that the sediment beds were oriented towards the mountain. Prof Snajeev Grupta, a Curiosity mission scientist, said that this systematic pattern was continually repeating and thus puzzling his research colleagues.
Prof Grupta said that the patterns suggested that running water was bringing sediments from Gale’s rim towards its center where it would have pooled as a static lake.
Over millions of years, the continuous accumulation of sediments has built up Mount Sharp layer by layer to its current height. The research team says that the mountain’s current shape is due to wind erosion that occurred in hundreds of millions of years.
Prof John Grotzinger was very pleased by Curiosity field work. He said that NASA researchers wouldn’t have been able to solve Mount Sharp’s puzzle by looking only at the data provided by satellites.
Prof Grotzinger told journalists that there was no way to have learned all this from orbit, while Curiosity also helped the research team not only to reach and learn about Mount Sharp’s creation, but also to appreciate it.