March's valleys were created by runoff, says new study

The contours observed on Mars may have been created by runoff, say the scientists who found that the ramification angles of the valleys on the red planet were very similar to those found in the arid landscapes on Earth. The surface of Mars bears imprints of structures that resemble fluvial steam systems on Earth. Scientists therefore badume that there must have been enough water on the red planet to feed the streams that have made their way into the soil.

For years, however, scientists have debated the source of this water. A study, published in Science Advances, suggests that the ramified structure of ancient river systems on Mars has striking similarities to terrestrial arid landscapes. Using statistics from all river valleys mapped on Mars, the researchers conclude that the contours still visible today must have been created by a superficial flow of rainwater.

Therefore, groundwater seepage can be excluded as a dominant process. to shape these features. The distribution of the ramification angles of the valleys on Mars is very similar to that of the arid landscapes of the Earth. This implies that there must have been a similar hydrologic environment with sporadic rainfall events on Mars for a prolonged period of time and that this rain water has quickly drained onto the surface shaping the valleys' networks.

in the arid regions of the Earth. For example, in Arizona, researchers observed the same valley network patterns in a landscape where astronauts train for future Martian missions. Valleys in arid regions form a narrow angle fork

The ramification angles on Mars are relatively low. Seybold therefore excludes the influence of groundwater shoots as a major channel-forming process on Mars. River networks formed by re-emerging groundwater, such as those found in Florida, for example, tend to have much wider branching angles between the two tributaries and do not correspond to the narrow angles of the river courses. Water in arid areas. Conditions such as those found today in arid and terrestrial landscapes have probably prevailed on Mars for a relatively short period of time, there are 3.6 to 3.8 billion of the years

. "Recent research shows that there must have been a lot more water on Mars than previously supposed," said Hansjorg Seybold, a professor at ETH Zurich.

One hypothesis suggests that the northern third of Mars was covered by an ocean at that time. Water evaporated, condensed around high upland volcanoes south of the ocean and resulted in heavy rainfall. As a result, the rivers formed, leaving traces that can still be seen on Mars today. The big question is where the water is gone over time. "It's likely that most of it has evaporated into space, but it could still be found in the vicinity of Mars, it's a question for a future space mission," Seybold said. .