Researchers have found that our immediate neighbour and the Red Planet, Mars loses its water at a much more faster rate than previously expected. This finding will potentially help to understand how the planet lost it’s water bodies.
The evidence that Mars harboured rivers and lakes comes from the occurrence of winding river valleys and dry lake beds found on the planet. Whatever water is remaining is locked in the polar ice caps found on the planet which now is dry and cold and these water remains constitute just 10% of what was once found in Mars.
The researches say that most of the water escaped directly into the atmosphere and was broken down in the upper atmosphere into hydrogen and oxygen by the UV rays from the sun directly hitting the planet. The hydrogen molecule, due to its light mass and Mars’s less gravitational pull, rises up into space.
Scientists are carrying out research on the distribution of water molecules at various levels of Mars’s atmosphere. They are focusing on how water is distributed up and down the atmosphere altitude wise. It was found that seasonal changes are the key factors determining this distribution.
The upper atmosphere was saturated with water vapour during the hottest season on the planet which surprised the scientists. There was 10 to 100 times more water vapour in space than the theoretically possible levels. According to the planetary scientist Frank Montmessin from the University of Paris Saclay in France, these extraordinary levels of saturation are found nowhere on any other body of the solar system.
The explanation for this phenomenon is that, when sunlight hits directly on the ice-covered surface, the water rises in the form of vapour into the atmosphere. Wind transports these water molecules towards the higher and colder altitudes where they combine with the dust particles to condense and form clouds thus preventing the escape of water into space or their rapid progression to higher altitudes.
The atmosphere is thus supersaturated and allows more and more water vapour to escape the surface and reach the atmosphere. The UV rays dissociate these water molecules into oxygen and hydrogen, allowing the hydrogen atoms to escape into space. This explains the loss of Martian waters over the years.
Montmessin said that “We must envision that water escape on Mars has been way more effective than previously thought”. He also added, “future research can better quantify how much water is entering the upper atmosphere and model its behaviour, so scientists and better understand how water vapour can escape into space”.