Physicists have determined that there used to be occasional showers on Mars.
The Martian surface is cut by channels from the once existing streams of water. An international team of scientists compared their geometry to Earth's ducts and concluded that rainfall fell four billion years ago on the Red Planet. The research is published in the journal Science Advances.
Previously, there were two versions of the origin of the channels. First: they appeared during the melting of ice during volcanic activity. Second, rainwater formed them. The conclusions about the history of the planet's climate depend on which theory is correct.
Scientists studied the angles at which streams of water branched, and compared them with earthly sources. They found that the angles are small (an average of 40 degrees) and resemble those found in arid regions such as the Arizona desert. Where rivers constantly renew their current, the branching angles are much wider. Therefore, scientists excluded the influence of groundwater and decided that the Martian streams appeared after heavy rains.
Two Martian Streams Scientists Selected for Comparisons / Science Advances.
Researchers estimate that the conditions found today in Earth's arid regions prevailed on Mars four billion years ago and lasted for about two hundred million years. According to the study's author Hansjörg Seybold, as the atmosphere disappeared, water also evaporated. He believes that it evaporated into space and may still be near Mars. The plausibility of this hypothesis remains to be tested.
Alexey Evglevsky