Mars Express discovered an ancient system of underground lakes on Mars.

There is a hypothesis that water was previously present on Mars in liquid form. In her favor testify

traces of a liquid river discovered by the Mars Express in the Nili Fossae area, where there is a clear boundary between the two hemispheres of the Red Planet.

Now researchers have discovered newevidence of the existence of liquid water on Mars in the past. They analyzed images of 24 impact craters in the northern hemisphere of Mars, from 1.4 to 3.1 km in depth. As a result, it turned out that along with most of them there are valleys formed by water flows, and in some craters - deep canals.

15 craters had fan-shaped shapes similar toriver deltas. Some had channels that looked like branching tributaries. Their surface turned out to be flat - probably, such a relief was formed by water accumulated in them. Clusters of rocks were found in 16 craters that looked like they were formed as a result of landslides.

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Earlier, the Russian-European space probe"ExoMars-TGO" made detailed maps of the distribution of water on the surface of Mars. Scientists, based on his data, compiled the first full-fledged maps of water both on Mars and under its surface.