Rivers on Mars may have been much deeper and colder than previously thought

Images from the Mars Perseverance rover indicate that a fast-flowing river could be found in Jezero Crater long ago. This dramatically changes our view of warm, wet Mars.

The Mars Rover Perseverance rover is currently exploring the top of a 250-meter-high hill of sedimentary rock. That rock is composed of undulating layers, which indicates that it was deposited by flowing water. Based on the images provided by Perseverance of the rock layers, scientists have attempted to create a picture of the waters that deposited sediments here long ago. In particular, they wondered if that water formed relatively shallow streams — something they had already found evidence of through the eyes of the Mars rover Curiosity in Gale crater — or if things might have been a little denser in Jezero crater.

rock layers
To that end, Perseverance took hundreds of images of rock layers, which the researchers then analyzed. And soon they discovered that the rock layers contain rather coarse sediments and even small pebbles. Researcher Libby Ives explains that this indicates that scientists did not find traces of an undulating stream here, but of a fast-flowing and very deep river. “The stronger the water flow, the easier it is to move larger pieces of material.”

amazing
The find in Jezero crater is amazing. Never before had researchers on Mars discovered traces of a river this deep and fast flowing. “It’s the first time we’ve seen such regions on Mars,” says researcher Katie Stack Morgan. “If we think about the rivers of Mars, we have to start thinking about them on a very different scale than we did before.”

Hot and humid
Research has shown that Mars today is cold and dry, but that was different a long time ago. Billions of years ago, the planet had a much thicker atmosphere, and therefore was not only warmer, but also wetter. The Mars probe Curiosity previously discovered that Mars had shallow rivers and even lakes at the time. However, Perseverance now reveals that Mars must have had deep, fast-flowing rivers simultaneously.

Scientists are very interested in the warm and wet period of Mars’ existence. Not in the least, because the planet was probably more livable then than it is now. Through observations of Mars rovers, among other things, they have been trying for years to get a better grip on how long that wet, warm period lasted, and how and why it ended.