Mars’ lakes and rivers existed nearly a billion year longer than previously thought

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Based on the recent data collected by NASA’s Mars Reconnaissance Orbiter, scientists have concluded that the planet’s lakes and streams actually existed much longer than previously thought. Created by melting snow, these expansive water bodies were still extant nearly a billion years after the end of Mars’ ‘wet era’, according to the new research.

The study comes after the Mars Orbiter captured new images of the Red Planet’s northern region that in turn point to the presence of a “considerable amount of water”, long after what scientists until believed was the end of its ‘wet era’. The finding, the researchers believe, enhances the possibility of Mars being home to microbial life once upon a time. Speaking about the discovery, Sharon Wilson from Smithsonian Institution and a member of the research team, said:

We discovered valleys that carried water into lake basins. Several lake basins filled and overflowed, indicating there was a considerable amount of water on the landscape during this time.

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The images were taken in the Arabia Terra, a vast region in the planet’s northern half possessing giant, ancient craters. The area, according to the team, is believed to be one of the oldest terrains on the Martian surface. For the research, the astronomers also studied corresponding data collected by the European Space Agency’s Mars Express as well as NASA’s Mars Global Surveyor. They came across distinct signs that point to a expansive water system similar to the Great Lakes in Northern America. Wilson added:

One of the lakes in this region was comparable in volume to Lake Tahoe.

Tahoe, for instance, contains an average of 37 trillion gallons (around 140 trillion liters) of water, which if spread can inundate the entire state of California in nearly 35 cm (or 14 inches) of water. As pointed out by the U.S. Department of Agriculture, the lake will take another 700 years to fill if drained completely. So, a single lake on Mars might have held that much water.

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According to Wilson, the Martian lake in question likely originated in a valley down south, coalescing into a huge, water-filled basin called Heart Lake towards the northern region. Holding over 670 cubic miles (approx. 2,790 cubic kilometers) of flowing water, the Heart Lake was part of an enormous network of lakes and water bodies spread over 90 miles (or 150 kilometers) across the Red Planet’s northern side.

Thanks to existing information about the area’s 22 craters, the researchers were able date the lakes as occurring between 2 and 3 billion years ago. This is actually more than one billion year after what scientists believed was the end of Mars’ ‘wet era’, resulting in the solidification of most of the planet’s liquid water. The team was reported saying:

The rate at which water flowed through these valleys is consistent with runoff from melting snow. These weren’t rushing rivers. They have simple drainage patterns and did not form deep or complex systems like the ancient valley networks from early Mars.

As part of the research, the astronomers have also uncovered similar evidence about lakes and rivers in the southern part of Mars, indicating that the so-called ‘wet regions’ were not a regional occurrence. The findings of the study were recently published in the Journal of Geophysical Research, Planets. The scientists explained:

Evidence for a snowmelt based hydrology and considerable depths of water on the landscape in Arabia supports a cold, wet, and possibly habitable environment late in Martian history.

Source: NASA

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