Venus, our "sister" planet, is often depicted as a hell, shrouded in thick clouds, where terrible hurricanes rage and terrible heat prevails. Its atmosphere, 90 times denser than Earth's, consists mainly of carbon dioxide, and the temperature reaches 462 degrees Celsius, making it the hottest planet in our solar system.
However, despite these extreme conditions, Venus once had liquid water on its surface. This became evident from the analysis of meteorites that fell on Earth, which are believed to come from Venus. These meteorites contain minerals that could only form in the presence of liquid water.
Where did the water of Venus go? This question has puzzled planetary scientists for decades. There are several theories that try to explain this loss:
1. Dissociative recombination:
This theory states that ultraviolet (UV) radiation from the Sun split water molecules into hydrogen and oxygen atoms. Hydrogen atoms, being lighter, could escape from the atmosphere of Venus into space, thanks to the low gravity of the planet.
2. Greenhouse effect:
Carbon dioxide, which makes up the bulk of Venus' atmosphere, acts as a powerful greenhouse gas, trapping the sun's heat. This led to an increase in the temperature of the planet, which, in turn, caused water to evaporate from the surface.
3. HCO+ ion:
This theory proposes that chemical reactions in Venus' atmosphere led to the formation of the HCO+ ion. This ion can capture hydrogen atoms, forming water molecules, which are then split by UV radiation, releasing hydrogen atoms that can escape from the atmosphere.
4. Missions to Venus:
Scientists hope that future missions to Venus will be able to shed more light on this mystery. These missions can collect data on the composition of the atmosphere, the geological history of the planet, and other factors that may have influenced the loss of water.
Understanding how Venus lost its water could help us better understand planetary evolution and the possibility of life on other planets. It may also have practical implications for terraforming, that is, turning uninhabitable planets into habitable ones.
Additional sources of information:
Solar system.
Department of Astronomy
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