Mars is known to be an arid desert, covered with red dust, dry lake beds, and craters. But it wasn’t always the case, Nasa’s Curiosity rover has discovered. The largest and most capable rover ever sent to Mars has revealed the first evidence that Mars once had a similar climate to Earth.
Launched in 2011, the Curiosity rover has been exploring the Gale crater, which is believed to be the place where a former lake existed and has a huge mountain of sediment nearly six kilometres high at its centre, according to an AFP report. New findings show that Mars once had a cyclic climate, alternating between wet and dry seasons, which could have been conducive to supporting life.
Previously, Nasa had discovered that billions of years ago rivers and vast lakes existed on the red planet. "We quickly realised that we were working in lakes and rivers deposits, but did not know what type of climate they were linked to," William Rapin, the study's lead author, told AFP.
In 2021, while going up the slope of the sediment mountain, the Curiosity rover found salt deposits forming a hexagonal pattern dated nearly four billion years ago. It was identified as cracks in dried mud. When a lake dries up, the mud cracks and when it fills up again, these cracks heal, Rapin told AFP.
Today, I'm celebrating my 11th landiversary! 🥳— Curiosity Rover (@MarsCuriosity) August 5, 2023
In this last year, I’ve surpassed 30km, spotted another meteorite, entered a new quadrant, and encountered my toughest climb yet.
I've got more science-ing to do - so here's to more exploring on the Red Planet! pic.twitter.com/Bon1lvYwKP
When this process is repeated many times, the cracks show up as hexagons. Hence, this is considered the first tangible proof that the red planet had a cyclical climate. On Earth, alternating wet and dry seasons could have made it possible for life to exist, the researchers told AFP.
Previously, the Curiosity rover, which recently celebrated its 11th “landiversary” on the red planet, had detected the presence of organic compounds, which are considered to be the building blocks of life on Mars. But these need the right conditions to support life. It can’t happen when the climate is too dry or too wet.
However, if Mars did support life, it was likely to be primitive single-celled microorganisms, not the aliens that one tends to reflexively imagine. “Over 11 years, we've found ample evidence that ancient Mars could have supported microbial life due to the Curiosity rover,” Ashwin Vasavada of Nasa's Jet Propulsion Laboratory said in a press statement. Now, this new evidence adds to the discussion about the origin of life on Mars.
It’s not possible to explore ancient terrain like Mars on Earth as the tectonic plates constantly shift. As the surface of Mars lacks tectonic plates, it retains a comprehensive geologic record of Mars' history, dating back as far as 4.3 billion years, according to a Science Alert report. Hence, scientists have found evidence of lakes and rivers and oceans that spread across the Martian surface eons ago. Studying the red planet could also help us understand how life began on Earth.