Earlier, lots of water flowed on the surface of the red planet, forming pools, lakes, and deep oceans. A new study reveals that a major portion of that water is trapped within the minerals in mars’ crust. The objective of the research is to challenge the theory that says that the Red Planet's water escaped into space as its atmosphere was stripped away by the sun’s radiation.
The Caltech/JPL team believes that around four billion years ago, Mars had enough water to have covered the whole planet in an ocean. It was about 100 to 1,500 meters deep. However, a billion years later, the planet became dry as it is currently. Caltech PhD candidate Eva Scheller (MS '20), lead author of a paper on the research that was published by the journal Science, said, “Atmospheric escape doesn't fully explain the data that we have for how much water actually once existed on Mars”.
As a part of the research, the team studied the quantity of water on Mars, in all its forms, that is, vapor, liquid, and ice. here are two stable isotopes of hydrogen. There is then, the heavy hydrogen and the light hydrogen. The heavy hydrogen has a proton and a neutron in the nucleus. The lighter hydrogen can easily escape the planet's gravity into space than its heavier counterpart. Due to this, the escape of a planet's water through the upper atmosphere would leave a significant signature on the ratio of deuterium to hydrogen in the planet's atmosphere. The study further proposes that the combination of two mechanisms explains the observed deuterium-to-hydrogen signal. The two mechanisms include the trapping of water in minerals in the planet's crust and the loss of water to the atmosphere.
According to the reports by Science Daily, Scheller's co-authors are Bethany Ehlmann said, “Atmospheric escape clearly had a role in water loss, but findings from the last decade of Mars missions have pointed to the fact that there was this huge reservoir of ancient hydrated minerals whose formation certainly decreased water availability over time”.