Chinese rover finds evidence that water existed on Mars longer than thought

The Chinese rover Zhurong has found evidence suggesting that water has existed on Mars for much longer than previously thought.

Zhurong landed on a large plain in Mars’ northern hemisphere called Utopia Planitia on May 15, 2021 – where NASA’s Viking lander 2 landed in 1976.

The rover’s main mission, which lasted three months, was to look for signs of ancient life. He investigated the minerals, environment, and distribution of water and ice in the plain, which is part of the largest northern impact basin on Mars. The rover continues to explore its landing site and send information to the Tianwen-1 orbiter that circles the planet.

Data returned from the rover’s initial survey suggests that the Utopia Planitia basin contained water during a period when many scientists believed Mars was dry and cold.

A study detailing the findings was published Wednesday in the journal Science Advances.

changing planet

Mars was once hot and humid billions of years ago, but something changed and caused the planet to become the arid, frozen wasteland 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 still ongoing.

“The most significant and innovative thing is that we found hydrated minerals at the landing site that is in the young Amazonian terrain, and these hydrated minerals are (indicators) for aquatic activities, such as groundwater,” said Yang Liu, lead author of the study. Liu, a researcher at the Key Space Weather Laboratory of the Chinese Academy of Sciences and the Center of Excellence in Comparative Planetology.

The researchers analyzed data from the Zhurong rover on the sediments and minerals found in the basin, as well as analysis performed by the rover’s various instruments in its surroundings. They found hydrated silica and sulfates, similar to hydrated minerals discovered by other missions studying different regions of the red planet.

The minerals were contained in brightly colored rocks, where the colors help to show their composition. The researchers determined that these rocks at the landing site form a layer of duricrust – a solid layer on the surface of the ground. This type of layer can form when a substantial amount of water, either rising up groundwater or melting underground ice, basically turns the soil into a hard crust as 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 landing sites on Mars, suggests that Utopia Planitia had a more active water cycle tens of millions of years ago than the previous ones. scientists expected.

This adds to the growing evidence uncovered by Martian missions that the red planet has gone through cycles of being wet and hot or dry and cold, rather than making lasting and dramatic climate change. These weather ebbs and flows could have been the result of active volcanoes or impacts from other celestial objects, Yang said.

Driving exploration

This discovery came as a surprise to the researchers, because previous observations by the orbiters did not find traces of hydrated minerals at the landing site. That’s why exploration using the rover was key, Yang said.

Utopia Planitia has been of interest to scientists because some speculate that the region was once home to an ocean.

“Thus, the discovery of hydrated minerals (has) significant insights into the geological and water history of the region and the climatic evolution of Mars,” Yang said.

Yang said he hopes the rover can analyze the layers of a crater on the plain to find more information about the water history in the region.

The findings also suggest that there may be “considerable reserves” 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 could be used as important water resources on Mars.”