Scientists just found the best places to look for ancient life on Mars

Raindrops once splashed across the surface of Mars, filling valleys and rushing through canyons toward what may have been a vast ocean. Now, researchers at the University of Texas have mapped the Red Planet's largest ancient river systems for the first time, identifying 16 massive drainage basins that could have harbored life billions of years ago.

"We've known for a long time that there were rivers on Mars," said co-author Timothy Goudge. "But we really didn't know the extent to which the rivers were organized in large drainage systems at the global scale."

By piecing together previously published data on Martian valleys, lakes, and river features, the team discovered watersheds covering areas larger than 100,000 square kilometers. While Earth boasts 91 such massive river systems, Mars has far fewer due to its lack of tectonic activity.

These ancient Martian waterways, though covering only 5% of the planet's terrain, were responsible for 42% of all river erosion on Mars. The sediments they carried likely concentrated nutrients in ways that could have supported microbial life, making these basins prime targets for future missions searching for signs of ancient organisms.