The Mars Orbiter finds the first trace of ancient giant water lakes beneath the planet


An ESA spacecraft has detected strong evidence that there was once under Mars a series of vast, interconnected groundwater lakes.

New discoveries revealed by the Mars Express Orbiter of the European Space Agency (ESA) show why one should never judge a book on its cover. While now an arid and desolate planet, with no sign of life, scientists have discovered geological evidence that at one point there was a system of ancient interconnected lakes below the surface of the earth. March.

Not only that, but the researchers behind the discovery, writing in the Journal of Geophysical Research, revealed that five of these dead lakes below the surface of the planet may contain minerals essential to the development of life.

Building on previous discoveries – including bypass channels and valleys, as well as detecting a pool of liquid water under the south pole of Mars – researchers wanted to see if models that had predicted such vast lakes were true.

Using the Mars Express orbiter, the researchers explored 24 deep craters in the northern hemisphere of the planet, with soils at about 4,000 meters under the arbitrary definition of "sea level".

This led to the discovery of features on the soils of these craters that could only be formed in the presence of water, ponds and flows that could change and shrink over time. time. Other features include channels carved into crater walls, valleys dug by groundwater sinking, and dark, curved deltas that would have formed when water levels rose and fell.

These water levels also seem to align with the proposed shores of what would have been the ocean of Mars, which would have existed between 3 and 4 billion years ago.

Infrared satellite map of waterways and ancient lakes under Mars.

This image shows the distribution of a number of deep craters (marked by dots) recently explored as part of a study on groundwater on Mars. Image: topography: NASA / MGS / MOLA; Distribution of craters: F Salese et al (2019)

"The contemporaries of a Martian ocean"

"We think this ocean could have connected to a system of underground lakes spanning the entire planet," said co-author Gian Gabriele Ori.

"These lakes would have existed about 3.5 billion years ago, so they could be contemporaries of a Martian ocean."

The five craters that really caught the attention of the researchers contained essential minerals at birth, including clays, carbonates and silicates. These were the only basins deep enough to intersect for a long time the part of the Mars crust saturated with water.

Dmitri Titov, a scientist with ESA's Mars Express project, said: "Such discoveries are extremely important. they help us identify the most promising areas of Mars to find signs of past life.

"It is particularly interesting to note that such a successful mission on the Red Planet, Mars Express, is now essential to help future missions, such as ExoMars, explore the planet in a way that different."

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