Undiscovered ancient lakes may have supported water on Mars

New analysis from researchers at University of Hong Kong (HKU) suggests that the number of ancient Martian lakes is much higher than previously estimated, changing our understanding of the spread of water on Mars.

The team conducted a meta-analysis of several years of satellite data showing evidence of lakes on Mars, and found that scientists may have significantly underestimated the number of Martian lakes that once existed. Results published in Nature Astronomy may advance our understanding of water on Mars and Possible old life on the red planet.

The spread of ancient Martian lakes

Lakes are bodies of water supplemented by precipitation, melting ice, rivers, and groundwater and are responsible for much of the life we ​​see on Earth. Although Mars today is a frozen desert, billions of years ago, scientists believe it was once home to ancient lakes. Water on Mars on a large scale may have once supported ancient life.

Joseph Michalsky, a geologist in the Department of Earth Sciences at the University of Hong Kong, commented: “We know of approximately 500 ancient lakes deposited on Mars, but nearly all of the lakes we know are larger than 100 km.2. But on Earth, 70% of lakes are smaller than this size, and they occur in cold environments where glaciers have retreated. These small lakes on Mars are difficult to identify by satellite remote sensing, but there are likely many small lakes. It is possible that at least 70% of the lakes on Mars have yet to be discovered.”

Scientists are monitoring these small lakes on Earth to understand climate change, which means the missing small lakes on Mars could contain vital information about the Red Planet’s past climates. The new research suggests that these ancient Martian lakes existed about 3,500 to 4,000 million years ago, but each may only have lasted for about 10,000 to 100,000 years. The results also indicate that Mars was mostly cold and dry, and the warming was intermittent for short periods.

Example of a large lake hosted from a crater on Mars (A) and a small lake hosted from permafrost on Mars. Both images show altitude data from the MOLA (Mars Orbital Laser Altimeter) instruments and HRSC High Resolution Stereo Camera) mounted on images from THEMIS (a) and CTX (b). Credit: ESA/JPL/NASA/ASU/MSSS

Michalsky explained: “Because of the low gravity on Mars and the pervasive, fine-grained soil, the lakes on Mars were very murky and probably did not allow light to penetrate deeply, which would have challenged photolithic life if they were present.”

Supporting life on Mars

The lakes are rich in water, nutrients, and energy sources necessary to support microbial life, including light for photosynthesis, making the lakes prominent targets for astrobiological exploration by Mars Rovers, such as NASA’s Perseverance currently on the planet.

However, Michalsky cautioned, “Not all lakes are created equal. In other words, some Martian lakes may be more interesting for microbial life than others because some lakes were large, deep, long-lived, and had a wide range of environments such as hydrothermal systems that would have been favorable.” To form a simple. Life.”

This means that it may be more effective to target large, ancient, and ecologically diverse lakes for future water exploration on Mars.

Dr. David Becker, an ecologist in the School of Biological Sciences at the University of Hong Kong, concluded: “Earth hosts many environments that could serve as analogues for other planets. From the harsh topography of Svalbard to the depths of Mono Lake – we can determine how to design tools to detect life in place. Another here at home. Most of these tools are aimed at discovering the remains and remnants of microbial life.”

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