While one team of scientists has solved a martian mystery, another team has kind of created another one. Here’s what we know. Once upon a time, a long, long time ago, Mars had water. Enough water that even today, we can see the effects of flowing rivers and streams on the landscape. Perseverance’s landing place, Jezero crater, was even once a lake.

Then at some point in Mars’ history, all that water went away. And since our first orbital images of Mars were captured even before Dr. Pamela was born, scientists have been trying to understand just why Mars lost its water and became the desert planet it is now.

In a new paper published in Science Advances, a team led by geophysical scientist Edwin Kite analyzed the tracks of those rivers, creating a timeline of the changes in elevation and even latitude of flowing water. They used all that data to run simulations, and they found… well, they found that changing the amount of carbon dioxide did exactly nothing.

Carbon dioxide is a greenhouse gas, which means the presence of CO2 in the atmosphere helps warm a planet. Losing that CO2 is a great explanation for why Mars’ water was able to dissipate out to space or froze and ended up underground. Except carbon dioxide loss is clearly not the reason Mars dried out.

Scientists working on this project are now planning to use both the Curiosity and Percy rovers to study their respective landing zones for evidence to support a different explanation. And we’ll, of course, update you when they learn more.

Just when you think you understand a planet…

More Information

University of Chicago press release

“Changing spatial distribution of water flow charts major change in Mars’s greenhouse effect,” Edwin S. Kite et al., 2022 May 25, Science Advances