Once flowing, now dry: Unlocking Mars' water mystery

The Brighter Side explores in a new article that Mars, once a planet filled with flowing water, is now a barren, dusty landscape marked by dry riverbeds and empty lake basins. Traces of ancient streams across the surface hint at a time when water was abundant. While some of that water remains trapped beneath the Martian surface, the whereabouts of the rest have remained a mystery—until now.

Thanks to NASA's Hubble Space Telescope and the Mars Atmosphere and Volatile Evolution (MAVEN) mission, scientists are uncovering clues about how Mars lost its water over billions of years. These tools are providing insights into the forces that transformed a once-wet planet into the dry, desolate world observed through telescopes today.

John Clarke, a researcher at Boston University’s Center for Space Physics, is leading the investigation. His team is focusing on two possible fates for Mars' lost water. "Some of it likely froze into the ground," Clarke explains. "The rest may have broken apart into hydrogen and oxygen, with the light hydrogen atoms escaping into space."

To study this, Clarke's team uses Hubble and MAVEN to track hydrogen atoms escaping from Mars' atmosphere. These real-time observations help scientists estimate how much water Mars has lost over time by revealing the current rate of hydrogen's escape.

By monitoring the escape of these atoms, the researchers are uncovering the history of Mars. As the data piles up, scientists are piecing together how the planet evolved from one with rivers and lakes to the dry, frozen world it is today.

Mars' atmosphere is more dynamic than previously thought. Clarke notes, "In recent years, scientists have found that Mars has an annual cycle that is much more dynamic than people expected 10 or 15 years ago." The new findings suggest that Mars' atmosphere experiences rapid changes, with water molecules rising and releasing hydrogen and deuterium more quickly when the planet is closer to the Sun. These discoveries offer valuable insight into the processes that have shaped Mars’ climate and contributed to its dramatic transformation over the last four billion years.

By Naila Huseynova