Using images sent by NASA's Curiosity rover, as well as computer programs for modeling erosion on Mars and machine learning, a group of scientists from the United States concluded that dried up riverbeds should be in most of the Martian craters. Thus, said the authors of the new study, in the distant past, the surface of the Red Planet may have been "dotted" with rivers, meaning there were many more of them than previously thought.
Today, Mars is a rather inhospitable world. The average temperature there reaches minus 63 degrees Celsius, although in summer during daylight hours near the equator it can rise to plus 25 or even plus 30. The Red Planet's atmosphere is 95 percent carbon dioxide. However, it is a hundred times more rarefied than the gas shell of the Earth, so it is not able to retain heat for a long time, even with this content of greenhouse gas. The surface of Mars is virtually defenseless against cosmic rays.
Mars was not always an "unfriendly" place. It had a dense atmosphere, and the climate there was wet and warm, it rained, and rivers flowed across the surface. Researchers believe that the Red Planet lost its "paradisiacal beauty" about three billion years ago. Then there was an event on Mars, because of which the magnetic field disappeared, somewhere went the bulk of the atmosphere, it was either carried away by the solar wind, or bound the soil, and the water turned into ice (is under the surface). So the Earth's neighbor became a cold and dry world, which experts today and observe.
How do scientists know that rivers flowed on Mars? The key evidence is ancient deposits of water streams (alluvial), which are found on the Martian surface by fluvial relief using probes and rovers. This type of topography is created by watercourses and is usually represented on Mars by canyons with thousands of dark lines, sandy landslides.
Until recently, geologists believed that Martian alluvial deposits could only be identified by fluvial formations. However, in new data that Curiosity sent back, researchers have found that this is far from the case. The rover observed water flow deposits in the Carolyn Shoemaker Formation in Gale Crater that were associated with a different type of terrain. The robot found them along a series of steep slopes, ledges and ledges. Scientists from the University of Pennsylvania (USA) said in their study, published in the journal Geophysical Research Letters.
"The rock formations observed by the Mars rover in Gale Crater are, in all likelihood, the remains of ancient riverbeds," explained the study's lead author Benjamin Cardenas.
To understand whether these rock formations could indeed have been formed by water and, if so, how often such structures might occur in Martian craters, Cardenas and his colleagues compiled the first numerical model simulating water erosion on Mars over millennia.
In developing the virtual map, the scientists used computer models trained on satellite images of the surface of Mars, images taken by Curiosity, and 3D scans of sedimentary rock layers that have been deposited over millions of years beneath the seafloor of the Gulf of Mexico. The latest data was provided by oil companies that collected the information while exploring the Gulf of Mexico seafloor.
The simulations showed that on Earth, such erosion can produce rock landforms (rather than fluvial relief) almost identical to the Martian ones captured by the Curiosity rover in Gale Crater.
The authors of the paper concluded that the steep slopes, ledges and ledges observed by the NASA rover can be used as indicators of ancient water deposits in Martian craters. American scientists have suggested that such structures would be found in most craters on the Red Planet, and if so, it could have had many more rivers in the past than previously thought. The abundance of rivers, according to the researchers, dramatically increases the likelihood that life may have once existed on Mars.