Where Did the Water on Mars Go?

Imagine what Mars must have been like billions of years ago. Scientists believe that life once existed on Mars and that there was liquid water flowing on the surface. This is shown through water-like erosion, like river deltas on the surface of Mars. Currently, on Mars, there are ice caps on the North and South poles. However, new studies and research shows that there may be an ocean’s worth of water underneath Mars's crust.

Mosaic of Mars Composed of 100
Images Captured by Viking Orbiters

A study done by JPL found that Mars was once wet enough to the point where its entire surface was covered with an ocean that was anywhere from 330 to 4920 feet deep. This ancient ocean on Mars contained half the amount of water in the Atlantic Ocean. This ocean gives the is a strong chance that there was once life on Mars. Now, Mars is a cold and dry place. Scientists believe that after Mars lost its magnetic field, it wasn’t protected from solar radiation and wind. This stripped a lot of the air and water on Mars. Today, Mars has a thin atmosphere and the only signs of water on its surface are the ice caps on the poles.

Concept Art of MAVEN Orbiter
Orbiting the Red Planet

However, data from NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) mission and the ESA’s Mars Express orbiter showed that Mars would have lost only 10 to 82 feet from a global ocean of water over a course of 4.5 billion years. Through this data, scientists hypothesized that much of the remaining water is hidden below the crust of Mars in crystal structures. 

Another theory says that water was lost because it escaped into space and crystalized in the freezing temperatures. To measure this, scientists are analyzing hydrogen levels within Mars’s atmosphere and its rocks. The reason behind this is very interesting. A hydrogen atom contains a proton in its nucleus, but some isotopes possess an extra neutron. This isotope is known as deuterium. Since hydrogen has a smaller mass than deuterium, regular hydrogen is able to escape from the planet’s gravity more easily. By comparing the levels of regular hydrogen and deuterium atoms in Martian soil, researchers can estimate the amount of regular hydrogen that Mars lost over a period of time. This is because water molecules are composed of two hydrogen atoms and one oxygen atom. Therefore, by estimating the hydrogen loss, scientists can reflect how much water has disappeared from Mars.

Studies have also found chemical reactions that may have led 30% to 99% of water than was on ancient Mars to get locked into minerals in Mars’s crust around 3 billion years ago. Despite all this, most researchers agree upon the fact that Mars lost 40% to 95% of its water during the Noachian period, which happened about 4.1 billion to 3.7 billion years ago. Scientists hope to use data from the Perseverance rover which landed on Mars a month ago to further prove their findings. Maybe in the next 50 years, we will have a colony on Mars harvesting water from the minerals in Mars’s crust.

Visualization of What Water Mining Could Be on Martian Colonies

Sources:

Choi, Charles Q. “Mars Colonists Could Get Fuel and Oxygen from Water on the Red Planet.” Space.com, Space, 2 Dec. 2020, www.space.com/mars-colonists-fuel-oxygen-production. 

Choi, Charles Q. “Mars May Hide Oceans of Water beneath Its Crust, Study Finds.” Space.com, Space, 16 Mar. 2021, www.space.com/mars-water-oceans-hiding-beneath-crust. 

Kramer, Miriam. “MAVEN: NASA's Orbiter Mission to Mars - Mission Details.” Space.com, Space, 19 July 2018, www.space.com/23617-nasa-maven-mars-mission.html. 

“New Study Challenges Long-Held Theory of Fate of Mars' Water.” NASA, NASA, www.jpl.nasa.gov/news/new-study-challenges-long-held-theory-of-fate-of-mars-water?utm_source=iContact&utm_medium=email&utm_campaign=nasajpl&utm_content=mars20210316-1. 

Summers, Vincent. “Heavy Water (Deuterium Oxide) –vs.– Regular (Tap) Water.” Quirky Science, 18 June 2020, www.quirkyscience.com/heavy-water/.