Curiosity's exploration of the Gediz Vallis Channel on Mars offers new insights into the planet's past, revealing a possible history of water flows and climate changes that challenges previous beliefs about Mars' dryness. Image source: NASA/JPL-Caltech/MSSS
The rover has reached an area where there may be evidence of liquid water flowing Mars For much longer than previously thought.
NASAThe Curiosity rover has begun exploring a new region on Mars, one that could reveal more about when liquid water disappeared once and for all from the Red Planet's surface. Billions of years ago, Mars was wetter and perhaps warmer than it is today. Curiosity takes a new look at that Earth-like past as it passes through, and eventually crosses, the Gedes Valles Canal, a sinuous, snake-like feature that — from space, at least — appears to have been carved by an ancient river.
This possibility has sparked the interest of scientists. The rover team is looking for evidence of how the channel was carved into the bedrock. The sides of the formation are steep enough that the team does not believe the channel was formed by wind. However, debris flows (fast wet landslides) or a river carrying rocks and sediments can have enough energy to burrow into the rock. After the channel was formed, it was filled with rocks and other debris. Scientists are also looking to find out whether these materials were transported by debris flows or dry avalanches.
After arriving at Gediz Valles, NASA's Mars rover Curiosity captured this 360-degree panoramic image using one of its black-and-white navigation cameras on February 3. This formation has piqued the curiosity of scientists because of what it may tell them about the history of water on Earth. Red planet. Image source: NASA/JPL-Caltech
Since 2014, Curiosity has been ascending the slopes of Mount Sharp, which lies 3 miles (5 kilometers) above the floor of Gale Crater. The layers in this lower part of the mountain formed over millions of years amid the changing Martian climate, providing scientists with a way to study how the presence of water and the chemical components needed for life changed over time.
For example, the lower part of these slopes had a rich layer Clay minerals Where a lot of water interacted with the rocks. The rover is now exploring a layer rich in sulfates, salty minerals that often form as water evaporates.
Pan through this 360-degree video to see the Gediz Vallis channel from the viewpoint of NASA's Curiosity Mars rover. Credit: NASA/Jet Propulsion Laboratory-California Institute of Technology
Review the Mount Sharp schedule
It will take months to fully explore the channel, and what scientists learn could alter the timeline of the mountain's formation.
Once the sedimentary layers of lower Mount Sharp were deposited by wind and water, erosion reduced them to reveal the layers visible today. Only after these long processes – as well as periods of severe drought during which the surface of Mount Sharp was a sandy desert – was it possible to carve the Gedes Valles Canal.
Scientists believe the rocks and other debris that then filled the channel came from up the mountain, where Curiosity would never reach, giving the team a glimpse into the types of materials that might be there.
The steep path taken by NASA's Curiosity Mars rover to reach the Gediz Vallis Channel is highlighted in yellow in this visualization made from orbital data. At the bottom right is the point where the rover swerved to get a closer look at a ridge formed long ago by debris flows from the top of Mount Sharp. Image source: NASA/JPL-Caltech/UC Berkeley
“If the channel or debris pile was formed by liquid water, that's really interesting. That means it's very late in the Mount Sharp story,” said Curiosity project scientist Ashwin Vasavada, of NASA's Jet Propulsion Laboratory in Southern California. “After a long drought – the water is back, and in a big way.”
This explanation would be consistent with one of the most surprising discoveries Curiosity made during its ascent of Mount Sharp: Water appears to come and go in stages, rather than gradually disappearing as the planet dries out. These cycles can be seen as evidence of clay fissures. Shallow and salty lakes. Just below the channel, the catastrophic debris flows that accumulated to form the sprawling Gedes Valles mountain range.
Last year, Curiosity made a challenging ascent mission to study the ridge, which runs across the slopes of Mount Sharp and appears to grow out of the end of the channel, suggesting that both are part of a single geological system.
Watch the channel closely
Curiosity documented the channel with a 360-degree black-and-white panorama from the rover's left navigation camera. The image, taken on February 3 (the mission's 4086th sol), shows dark sand filling one side of the channel and a pile of debris rising just beyond the sand. In the opposite direction is the steep slope that Curiosity climbed to reach this area.
The rover takes these types of panoramas with its navigation cameras at the end of each trip. The science team is now relying more on navigation cameras as engineers try to solve a problem that limits the use of a single imaging device belonging to the color Mast Camera, or Mastcam.