NASA rover finds spot where ‘exciting’ events took place on Mars

There were once great floods that flowed down from a high mountain on Mars.

And NASA’s dust-covered Curiosity rover has proof.

NASA’s car-sized robot has spent much of 2024 exploring the Gediz Vallis Channel, a dried-up waterway that flows across the three-mile-high Mount Sharp. Although Mars is today 1,000 times drier than the driest desert on Earth, the rover has found evidence that the Red Planet experienced massive flooding long ago. It was a wet world.

“This was not a quiet period on Mars,” Becky Williams, a scientist at the Planetary Science Institute who is studying Mars using the rover’s Mast Camera, said in a statement. “There was an exciting amount of activity here. We’re looking at multiple currents in the channel, including energetic flooding and boulder-heavy currents.”

The images below show what Curiosity recently found.

Below is a wide-angle photo of part of Gediz Vallis as it descends Mount Sharp. You can see striking piles of rocks and boulders, like the one in the foreground on the left. “This area was likely formed by large floods of water and debris that piled up the rocks into mounds in the channel,” NASA explained. Impressively, this debris pile extends down the mountain for about two miles (although some of this was likely caused by landslides as well).

The Gediz Vallis channel on Mars showing large accumulations of rocky debris.
Source: NASA / JPL-Caltech / MSSS

Curiosity also took a close look at these water-tumbled rocks. Several of them have telltale “halo” markings, as seen in the image below. “Eventually, the water soaked into all of the material that settled here,” the space agency explained. “Chemical reactions caused by the water turned out to be white ‘halo’ shapes in some of the rocks.”

At center is a Martian rock with a clear “halo” created by ancient interactions with water.
Source: NASA / JPL-Caltech / MSSS

Unlike Earth, Mars no longer has an insulating atmosphere. The Red Planet’s hot metallic core deep beneath the surface cooled long ago, and without a heated interior to generate a protective magnetic field, the once-watery world was exposed to a relentless stream of particles from the sun, called the solar wind. The solar wind gradually stripped Mars of its thick atmosphere, leaving it the frigid, unfeeling, irradiated desert we see today.

The Curiosity rover, which landed on Mars in 2012, continues to scour the planet to determine whether the planet could once have supported habitable conditions for microbial life. Meanwhile, NASA’s Perseverance rover, which landed in 2020, is equipped with instruments that search for clues to past life, called “biosignatures” — elements, substances or features that provide evidence of ancient organisms. These could be telltale strings of molecules or structures that were almost certainly produced by single-celled Martians.

While it is clear that Mars was once home to abundant water, robotic explorers on Mars have so far found no evidence that life ever existed on this rocky world.