With the help of China’s Zhurong rover, scientists have obtained new evidence that Mars hosted an ocean billions of years ago, when it was a very different planet from the arid and desolate world of today, reports Reuters.
Researchers said Thursday that data obtained by the Zhurong rover, which visited the northern plains of Mars in 2021, and by space probes placed in Martian orbit indicated the presence of geological features that indicate an ancient coastline. The Chinese rover analyzed rocks from the surface of Mars in an area called “Utopia Planitia”, a large plain located in the northern hemisphere of the “Red Planet”.
According to scientists, data from China’s Tianwen-1 Orbiter, NASA’s Mars Reconnaissance Orbiter and Zhurong – a robotic six-wheeled rover – indicated the existence of a water ocean at a time when Mars may have already become cold and arid and to have lost a large part of its atmosphere.
They described surface features such as troughs, sediment channels and mud volcano formations that indicate a coastline, with evidence of both shallow and deep marine environments.
“We estimate that the flooding of Utopia Planitia on Mars occurred about 3.68 billion years ago. The ocean surface was probably frozen in a short geological period,” said Bo Wu, a planetary science researcher at the Hong Kong Polytechnic University Kong and lead author of the study published in the journal Scientific Reports.
That ocean appears to have disappeared about 3.42 billion years ago, the authors of the research added.
“The water was heavily sedimented, forming the layered structure of the deposits,” explained Sergey Krasilnikov, researcher in planetary sciences at the Hong Kong Polytechnic University and co-author of the study.
Like Earth and the other planets in the Solar System, Mars formed about 4.5 billion years ago. By the time that ocean appears to have existed, Mars may have already begun transitioning away from its hospitable planet status.
“The presence of an ancient ocean on Mars has been a theory proposed and studied for decades, but significant uncertainty remains. These findings not only provide additional evidence in support of the theory of a Martian ocean, but also present, for the first time, the basis of a discussions about its likely evolutionary scenario,” Bo Wu said.
Water is considered a key ingredient for life, and the past presence of an ocean raises the prospect that Mars may have been capable, at least at one point, of hosting microbial life.
“Early in the history of Mars, when this planet probably had a thick and warm atmosphere, microbial life was much more likely,” said Sergey Krasilnikov.
The solar-powered Zhurong rover, named after the god of fire in Chinese mythology, began work using its six scientific instruments on the Martian surface in May 2021 and then went into hibernation in May 2022, likely due to excessive accumulation of sand and dust, according to the designer of his mission. The Chinese rover exceeded its planned duration of operation within this mission, which was originally three months.
Researchers have tried to better understand what happened to all that water that was once present on the surface of the planet Mars. Another study, published in August and based on seismic data obtained by NASA’s InSight robotic probe, indicated that a huge reservoir of liquid water could be hidden deep beneath the Martian crust, among fractured igneous rocks.
