Planetary scientists, based on data from the MAVEN interplanetary station, have found out why all the water reserves from Mars evaporated into space.
Previously, the climate of Mars was warm and humid: in some ways, it resembled the earthly one. However, after a while, all the water from the Red Planet evaporated into space, and this process continues. According to the generally accepted theory, water first disintegrated into hydrogen molecules, and only then these molecules escaped into space.
In the past, few people believed that water could in principle exist in the upper atmosphere of Mars. Our calculations show that over the past billion years, this part of the planet’s air envelope has lost as much water as it would have been enough to cover its surface with an ocean 44 cm thick. Mars lost another 17 cm of water due to dust storms.
Based on data from the orbiting probe MAVEN (Mars Atmosphere and Volatile EvolutioN), scientists have put forward a new hypothesis about why Mars became lifeless at one point. Analyzing information from the station, the authors of the article realized that water molecules somehow slip through the protective atmospheric barrier much more easily than previously thought.
They suggested that somewhere at an altitude of 50-60 km and above, where the so-called gygropause is located, this barrier protects the earth’s water, keeping it in the clouds and preventing hydrogen from “escaping” into space.
Scientists have used MAVEN probe instruments to find out where the hygropause is and the typical amount of water on both sides. It turned out that it was not at all impervious to water vapor. Accordingly, the liquid in the upper atmosphere of Mars is present throughout the year. In the upper atmosphere, its concentration increased sharply in the summer in the southern hemisphere of Mars and during powerful dust storms.
Based on this, it was concluded that water from Mars enters space directly. It rises to the upper layers of its atmosphere, where it begins to interact with cosmic rays and the solar wind. The next step in exploring the planet will be to find the exact or approximate time period when this process began.