Scientists are rethinking the cause of water loss on Mars in the face of new evidence that challenges the long-held theory that the water may have evaporated into space. That’s according to new NASA-funded research published this week in the journal Science.
Researchers hypothesize that about 30% and 99% of the water on Mars may have been lost to the crust, likely trapped within the minerals there.
The lead author of the study, Eva Scheller, said “the water was lost by 3 billion years ago, meaning Mars has been the dry planet it is today for the past 3 billion years.”
Once upon 3 billion years ago, Mars was covered with plentiful water that collected into pools, lakes, and deep oceans about half the volume of Earth’s Atlantic Ocean, researchers concluded based on geological evidence.
In search of the missing water, scientists believed water on the Martian crust escaped through the atmosphere because of low gravity on the red planet.
Now that theory is being challenged by a new study that theorizes a new model to explain the loss of water.
“Atmospheric escape doesn’t fully explain the data that we have for how much water actually once existed on Mars,” she said.
Scheller further disclosed that there are three key processes within their model.
“Water input from volcanism, water loss to space and water loss to the crust.”
She said the model allowed them to match their hydrogen isotope data set in order to calculate the amount of water lost to space and that which was lost to crust.
Presenting the study at the 52nd Lunar and Planetary Science Conference, the Caltech Ph.D. candidate explained the research findings are based on the fact that not all hydrogen atoms are the same.
There is the most common hydrogen which contains a proton and the less common variant that comprises both proton and neutron. This type is widely referred to as the deuterium or "heavy” hydrogen.
When water is lost on a surface, lighter hydrogen atoms defy gravity quicker, leaving behind the “heavy” hydrogen.
But the researchers said the amount of the deuterium-to-hydrogen ratio observed in the Martian atmosphere and large amounts of water in the past does not support this theory.