Mar 18, 2021 07:00:00

The large amount of water that disappeared from Mars may be trapped in minerals

by

NASA's Marshall Space Flight Center

Mars, which has been exploring in recent years, is thought to have been a planet covered with the same water as the Earth, but now it has a dry surface. When asked, 'Where did the water that should have been on Mars go?', A new treatise published by a research team at the California Institute of Technology said, 'A large amount of water may be trapped in Martian minerals. There is. '

Long-term drying of Mars by sequestration of ocean-scale volumes of water in the crust | Science
https://science.sciencemag.org/content/early/2021/03/15/science.abc7717

What happened to Mars's water? It is still trapped there: New data challenges the long-held theory that all of Mars's water escaped into space --ScienceDaily
https://www.sciencedaily.com/releases/2021/03/210316132106.htm

Mars' Vanished Oceans May Be Trapped Within The Planet, Scientists Say
https://www.sciencealert.com/study-says-it-s-knows-where-mars-missing-water-is

It is said that a large amount of water once existed on Mars, and it is thought that about 4 billion years ago, there was a 'sea' with a depth of 100 to 1500 meters. However, the water on Mars dissipates over time, and even if you look at the pictures of the surface of Mars taken by NASA's Mars probe 'Perseverance', you can only see how the desolate land is spreading.

NASA releases panoramic photos of Mars with over 400 million pixels & more than 2000 raw data --GIGAZINE

As for the question, 'Where did the large amount of water disappear?', The water vapor contained in the atmosphere of Mars escaped to outer space together with the atmosphere due to weak gravity and the solar wind. There is a theory that it was. It has also been pointed out that there may be ice beneath Mars.

To answer this question, a research team at the California Institute of Technology and NASA's Jet Propulsion Laboratory conducted an analysis using data from a Mars probe and meteorites flying from Mars. In addition to investigating the amount of water present on Mars in the form of steam, liquid, and ice, and the chemical composition of the atmosphere and crust, the analysis focused on the 'type of hydrogen.'

Deuterium is nucleus is proton one and the neutron is an isotope of hydrogen, which is composed of one, the nucleus has become a thing heavier than common hydrogen, which is composed of one proton. The ratio of deuterium to hydrogen is said to be 0.02%, but since ordinary hydrogen is lighter than deuterium and easily dissipates into outer space together with the atmosphere, if the water on Mars escaped into outer space. If so, the proportion of deuterium left on Mars is expected to be higher than normal.

However, considering the amount of water originally on Mars and the amount of hydrogen escaping from Mars to outer space, the current ratio of deuterium to hydrogen on Mars cannot be explained by atmospheric loss alone. From this result, the research team not only escaped the water on Mars to outer space through the atmosphere, but also proposed the theory that 'water is trapped in minerals in the crust'.

'Atmospheric dissipation does not fully explain the data on the amount of water that once existed on Mars,' said Eva Scheller, a PhD student at the California Institute of Technology. According to a simulation conducted by the research team, 30-99% of the water that existed on Mars may be trapped in minerals in the crust.

It is not only Mars that minerals react with water and trap water in the minerals, but

hydrous minerals in which water is incorporated into the crystal structure of minerals also exist on Earth. However, on Earth, water in minerals is released into the atmosphere through volcanic activity and circulates, so water does not remain trapped in minerals.

On the other hand, since Mars has no volcanic activity, the water trapped in the minerals does not circulate and remains in the atmosphere. 'This water was quarantined quite early on and never circulated back,' Scheller said. Research team simulations suggest that most of Mars' water was lost between about 4 and 3.7 billion years ago, and about 3 billion years ago it was almost as dry as it is today. It is believed to have been.

Professor Bethany Ehlmann, co-author of the treatise, said, 'Although atmospheric dissipation has clearly had a clear impact on water loss, the findings of the Mars mission over the past decade show water availability as it forms. It points to the fact that there was a reduced'water reservoir of ancient hydrous minerals'. '

Mr. Scheller said that he has high expectations for the perseverance of the Mars probe that has been in operation since February 2021. By collating the data collected by Perseverance with the research team's model, he claims that he can understand the right and wrong parts of the simulation-derived model and get closer to a more accurate answer.