Water Flows on Mars Longer Than Previously Thought

TEMPO.CO, Jakarta – So far it has been believed that the water that once existed in Mars evaporated about 3 billion years ago. It seems that belief will have to be revised in line with the latest findings. A team of geological and planetary researchers from the California Institute of Technology, USA, used NASA’s Mars Reconnaissance Orbiter (MRO) to determine when surface water left mineral salts on the Martian surface.

The team of two scientists studied data that the MRO has collected on Mars over the past 15 years. As a result, they have found evidence that reduces that timeline significantly: the last signs of liquid water on the red planet 2 to 2.5 billion years ago.

The results of the data mean that water flows on Mars about a billion years longer than previously thought. The findings were published in AGU Advances on 27 December 2021.

Mars is thought to have been filled with rivers and lakes billions of years ago. As the planet’s atmosphere thins over time, the water then evaporates, leaving a frozen desert world. And this is exactly what NASA’s Mars Reconnaissance Orbiter (MRO) is studying today.

His discussion centers on salt chloride deposits that are left behind as meltwater flowing across the landscape evaporates. While the shape of the particular valley network suggests that water may have flowed there, the salt deposits provide the first mineral evidence to confirm the presence of water on Mars.

The discovery raises new questions about how long microbial life could last on Mars, if water ever formed. Compared to Earth, where there is water, there must be life.

Ellen Leask and Bethany Ehlmann, two of the researchers, used data from an MRO instrument called the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) to map chloride salts across clay-rich plateaus in Mars’ southern hemisphere. This location is said to be filled with impact craters.

Planet Mars. Photo: NASA

These craters are one of the keys to determining the age of the salt. The fewer craters a terrain has, the younger it is. By counting the number of craters on a surface area, scientists can estimate their age.

MRO has two cameras that are perfect for that purpose. The Context Camera, with its black-and-white wide-angle lens, helped scientists map chloride levels. To zoom in, the scientists turned to the High-Resolution Imaging Science Experiment (HiRISE) color camera, allowing them to see as much detail as an on-situ Martian rover.

Using the two cameras to create digital elevation maps, Leask and Ehlmann found that much of the salt was in depressions — once home to shallow lakes — on gently sloping volcanic plains. Scientists also found winding dry channels nearby — former rivers that once drained surface water (from melting ice or the occasional permafrost) into the pools.

The Mars Reconnaissance Orbiter (MRO) probe has mapped former rivers buried beneath the red planet’s surface. Clarksvilleonline.com

Counting of the craters and evidence of salt over the volcanic terrain allowed them to date the deposits. “What’s amazing is that after more than a decade of providing high-resolution image, stereo, and infrared data, MRO has driven new discoveries about the nature and timing of the ancient salt farms connected to this river,” said Ehlmann.

The mineral salt was first discovered 14 years ago by Odyssey, the Mars orbiter belonging to NASA, which was launched in 2001. While the MRO, which has higher resolution instruments than the Odyssey, was launched in 2005. The MRO orbits near the poles at an altitude ranging from 255 kilometers (158 miles) to 320 kilometers (199 miles). Working time per orbit 112 minutes.

NASA

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