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China’s Zhurong rover has found evidence suggesting that water persisted on Mars for much longer than expected.
Zhurong touched down on a large plain in the northern hemisphere of Mars called Utopia Planitia on May 15, 2021, where NASA’s Viking 2 lander touched down in 1976.
The rover’s primary mission, which lasted three months, was to search for signs of ancient life. He has investigated the minerals, environment, and distribution of water and ice in the plain, which is part of the largest impact basin in the northern lowlands of Mars. The rover continues to explore its landing site and sends information to the Tianwen-1 orbiter that circles the planet.
Data from the rover’s initial study of the basin suggests that the Utopia Planitia basin contained water during a time when many scientists believed Mars was dry and cold.
A study detailing the findings published Wednesday in the journal Science Advances.
Mars was once hot and humid billions of years ago, but something changed and caused the planet to become the arid, icy desert it is today. The Red Planet entered this period during what is called the Amazonian epoch, which began about 3 billion years ago and is ongoing.
“What is most significant and novel is that we found hydrated minerals at the landing site which is in the young Amazonian terrain, and these hydrated minerals are (indicators) for aquatic activities, such as (groundwater) activities,” said the author. principal of the study, Yang. Liu, a researcher at the Chinese Academy of Sciences’ State Key Space Weather Laboratory and the academy’s Comparative Planetology Center of Excellence.
The researchers analyzed data from the Zhurong rover on the sediments and minerals found in the basin, as well as analysis by several of the rover’s instruments of its environment. They found hydrated silica and sulfates, similar to the hydrated minerals discovered by other missions studying different regions of the red planet.
The minerals were contained within brightly hued rocks, where the colors help show their composition. The researchers determined that these rocks at the landing site form a layer of hard crust. This type of layer can form when a substantial amount of water, either rising groundwater or subsurface ice melts, essentially turning the soil into a hard crust once the water evaporates.
The discovery of this layer of duricrust, which is thicker than the duricrust likely formed by atmospheric water vapor found at other Martian landing sites, suggests that Utopia Planitia had a more active water cycle tens of millions of years ago than is known. What scientists expected.
This adds to mounting evidence uncovered by Mars missions that the Red Planet went through cycles of being wet and warm, and dry and cold, rather than making long-lasting, dramatic climate change. These climatic ebbs and flows may have been the result of active volcanoes or impacts from other celestial objects, Yang said.
This discovery came as a surprise to the researchers because previous orbiter observations did not uncover the signature of hydrated minerals at the landing site. That’s why the exploration using the rover was key, Yang said.
Utopia Planitia has been of interest to scientists because some speculate that the region once hosted an ocean.
“So the discovery of hydrated minerals (has) significant indications about the geological and water history of the region and the climatic evolution of Mars,” said Yang.
Yang said he hopes the rover can analyze layers of a crater in the plain to find more information about the history of water in the region.
The findings also suggest there could be “sizable stores” of water in hydrated minerals or even ground ice, which future human explorers could use during manned missions to Mars.
“One of the most important resources for human explorers is water,” Yang said. “Hydrated minerals, which contain structural water and ground ice, can be used as an important water resource on Mars.”