TEMPO.CO, Jakarta – Mars is believed to have been a wet planet, with lots of water on its surface. However, conditions changed dramatically billions of years ago, leaving behind the landscapes that are known today.
A PhD candidate from the California Institute of Technology, United States, Eva Scheller, explained that about 30-99 percent of the water may now be trapped in minerals in the Mars crust. The results of his study, published in the journal Science, published Tuesday, March 16, 2021, contradict the long-held assumption that water simply disappears into space through atmosphere.
“Water lost 3 billion years ago, which means Mars has become the dry planet it is today for the last 3 billion years,” he said as quoted by Reuters, Wednesday, March 17, 2021.
Early in its history, the Red Planet probably had surface water with a volume roughly the equivalent of half that of the Atlantic Ocean. This is enough to cover the entire planet with water that is probably nearly a mile (1.5 km) deep.
Water is composed of a molecule of one oxygen atom and two hydrogens. The number of the hydrogen isotope, or a variant called deuterium, that exists on Mars provides some clues about water loss. Unlike most hydrogens, which have only one proton in their atomic nucleus, deuterium — or “heavy” hydrogen — offers both protons and neutrons.
Ordinary hydrogen can escape through the atmosphere into space more easily than deuterium. The loss of water through the atmosphere, according to scientists, will leave traces of a very large ratio of deuterium compared to ordinary hydrogen.
Scheller et al. Used a model that simulates the isotope composition of hydrogen and the volume of Mars water. According to Scheller, who is also the lead author of the NASA-funded study, there are three main processes in this model: water input from volcanism, water loss into space, and water loss to the crust.
“By modeling this and matching it with the hydrogen isotope data set, we can calculate how much water is lost to space and the crust,” said Scheller.
Researchers suspect that much of the water doesn’t actually leave Mars but is trapped in various minerals as part of its mineral structure — especially clay and sulfates.
This trapped water, while seemingly plentiful when taken in its entirety, may not have provided the practical resources for astronaut missions to Mars in the future. “The amount of water in rocks or minerals is very small. You have to heat a lot of rocks to release a considerable amount of water, ”Scheller said.
REUTERS | SCIENCE