Nasa’s Mars Curiosity Rover mission has uncovered compelling evidence that physical, chemical and energetic conditions were present on an ancient Mars lake about 3.8 billion years ago and are believed to exhibit proof of a habitable environment.
The lake found upon the Gale crater on Mars is believed to have hosted a variety of microbial life and led to an environment which could have supported a diverse array of living things.
The Curiosity Rover on its mission to Mount Sharp, landed on the Gale Crater in 2012. Upon sensing evidence of chemical ingredients and past lake water it drilled, x-rayed and laser blasted a variety of rocks in an effort to understand if the planet was hospitable to life.
The Curiosity orbiting instruments have detected signatures of both clay minerals and sulfate salts. Mars scientists have several important hypotheses about how these minerals may reflect changes in the amount of water on the surface of Mars. These rocks also serve as a study in the search for organic molecules and their ability to support microbial life.
Scientists will study how organic molecules, if present, vary with mineralogical variations in the layers to understand how they formed and what influences their preservation.
WHAT IS THE GALE CRATER LIKE?
Named after Walter F. Gale, an amateur astronomer from Australia, the Gale Crater spans 154 km in diameter and is roughly the size of Connecticut and Rhode Island. Scientists chose the Gale Crater as its landing site because it exhibited signs of water being present before.
The Gale Crater contains a single mountain known as Mt. Sharp and has a number of smaller hills on its surface. The smaller hills may provide clues to the modern water cycle on Mars. During summer, some of that water may have been released into the atmosphere. As temperatures cool, they may absorb water from the atmosphere.
The Mars Science Laboratory team will investigate how water is exchanged between these minerals and the atmosphere, helping us understand Mars’ modern climate. The hills are particularly useful for this investigation because different parts of the hills are exposed to different amounts of sunlight and thus to different temperatures. Curiosity will be able to compare the water in these contrasting areas as part of its investigations.
Scientists working on the project noticed a strange pattern in a stretch of layered rock. Regions of coarse sediment and finer-grained sediment were found and opened up different possibilities.
The coarse sediments had been rapidly dumped exhibiting shallow areas where water from a stream or river could flow into the lake and drop its material.
The finer grained sediments were layered more gradually, closer to the middle of the lake and panning out from the river mouth.
What scientists discovered was, minerals in the shallower parts of the lake were more exposed to oxygen than in the deeper areas. This is reminiscent of water bodies on Earth and paved the way to understanding the past environment.
“It’s that relationship between the mineralogy and the thickness of the sediment layers that allows us to connect the dots,” said study co-author Ashwin Vasavada, the mission’s project scientist at Jet Propulsion Laboratory.
WAS MARS HABITABLE IN THE PAST
Like the lakes on Earth, the one in Gale Crater could have hosted a variety of microorganisms, including some that preferred the oxygenated waters near the surface, others who preferred the anoxic waters deeper down, and those who liked to hang out at the interface between the two. The scientists also found that Mars seemed to progress from a colder, drier environment to a warmer, wetter one.
On top of that, its layers of sedimentary record were modified by what appears to be briny liquid. Studying these rocks could help scientists understand the ultimate drying of Mars as its water escaped to space, leaving the salts behind.
WHAT THIS MEANS
The Curiosity mission was designed to determine whether environments are habitable, not inhabited and thus we have to wait for future missions to determine if the planet is truly habitable. For now, the discovery of the environment on Mars is a huge step towards a sustainable future on other planets.
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Video Credits: National Geographic