Did Mars have lakes and rivers during a single period or over separate periods? This is what a recent study published in Nature Geoscience hopes to address as an international team of researchers investigated whether Mars experienced a single event of liquid water on its surface, or many events spread over millions of years. This study has the potential to help scientists better understand the early conditions on Mars and whether these conditions were suitable to support life as we know it.
“Early Mars is a lost world, but it can be reconstructed in great detail if we ask the right questions,” said Dr. Robin Wordsworth, who is a Gordon McKay Professor of Environmental Science and Engineering at Harvard University and a co-author on the study. “This study synthesizes atmospheric chemistry and climate for the first time, to make some striking new predictions – which are testable once we bring Mars rocks back to Earth.”
For the study, the researchers used a series of computer models to simulate how the atmosphere on Mars billions of years ago potentially reacted to surface water-rock interactions and climate changes over time. The goal was to ascertain whether Mars experienced a single event of liquid water on its surface, or a series of events spread over millions of years with periods of dryness in between them.
In the end, the team discovered that hydrogen escaping from the surface combined with volcanic activity billions of years ago could have resulted in periodic episodes of warm temperatures across the surface spanning approximately 40 million years with each episode lasting approximately 100,000 years. They concluded that atmospheric carbon dioxide declines could have resulted from surface absorption or changes in Mars’ axial tilt, resulting in the cold climate we see today.
Credit: ESO/M. Kornmess
“We’ve identified time scales for all of these alternations,” said Dr. Danica Adams, who is a NASA Sagan Postdoctoral Fellow at Harvard University and lead author of the study. “And we’ve described all the pieces in the same photochemical model.”
Going forward, the team aspires to examine rock samples returned to Earth via NASA’s Mars Sample Return mission, which is slated to occur sometime in the 2030s. In the meantime, these findings still question if life as we know it had the appropriate amount of time to begin due to the periodic episodes of warm and cold across the surface over millions of years.
What new discoveries will researchers make about past water on Mars in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: Nature Geoscience, EurekAlert!, Harvard University, NASA
Featured Image: Ancient Mars with liquid water oceans. (Credit: NASA/MAVEN/Lunar and Planetary Institute)
