A Chinese Mars rover may have found evidence of an ancient ocean on the arid Red Planet.
According to a new paper in the journal Scientific Reports, China's Zhurong rover has discovered traces of special features that could indicate an ocean existed long ago around Mars' Utopia Planitia region-located in its Northern Hemisphere.
These features include "pitted cones," as well as "pancake-like ejecta, polygonal troughs, and etched flows," the researchers wrote in the paper. "The Utopia Planitia region on Mars exhibits water-related features on its surface."
The researchers also noted that these findings do not necessarily prove the existence of an ancient ocean, as they could have formed without the presence of water. Additionally, some people have said they are skeptical about the study's claims.
Zhurong, part of the Tianwen-1 mission, successfully landed on Mars on May 15, 2021, in the Utopia Planitia region. This area was selected because of its flat terrain, which increased the chances of a safe landing, and its potential for scientific discoveries.
Utopia Planitia is situated in the northern lowlands of Mars, within the larger Utopia impact basin, one of the largest known impact craters in the solar system. It spans thousands of kilometers, with an area estimated to be roughly 2,000 miles in diameter. Some parts of Utopia Planitia show polygonal patterns on the surface, which may indicate past freeze-thaw cycles, possibly linked to subsurface ice.
The idea that Mars was once covered in water has been around for many years, but it is yet to be definitively proven. Mars lost much of its atmosphere over time due to its weak magnetic field. The thin atmosphere doesn't exert enough pressure for liquid water to remain stable on the surface, so it either sublimates directly from ice to vapor or remains frozen.
Geochemical analysis from Zhurong suggests that the potential ocean on Mars may have formed some 3.7 billion years ago due to flooding, before freezing and disappearing around 3.4 billion years ago.
Previous research on Mars has found that pitted cone structures may have resulted from mud volcanoes, forming in areas where water or ice may have been present.
"Pitted cones are small cone-like structures with summit pits and are common on the vast plains in the northern lowlands of Mars. Different mechanisms have been suggested for the formation of pitted cones, including mud volcanism," the researchers wrote.
The rover's analysis, as well as satellite data from the Mars Orbiter Laser Altimeter satellite, suggest that the troughs and sediment channels may be traces of the ocean's coastline in the region, carved out when the water froze over.
However, the researchers noted: "In situ measurements by sensors onboard the Zhurong rover hardly provide direct evidence of the existence of an ancient ocean; however, they do not contradict this model and could be considered within the context of ocean theory."
"The water-related minerals, such as hydrated silica (mainly opal and imogolite) and allophane, identified by MarSCoDe, could have formed under conditions unrelated to the ocean theory, but they could also have formed in the short-lived frozen Hesperian ocean."
Additionally, Benjamin Cardenas, a Martian researcher at Pennsylvania State University who was not involved in the study, told AFP that he was "skeptical" of the findings. He claims that the Martian wind would likely have worn down the rocks and sediment over the past few billion years, which would have destroyed evidence of an ancient ocean's coastline.
"We tend to think of Mars of being not very active, like the moon, but it is active!" Cardenas said.
The Zhurong rover won't be able to travel north to further investigate signs of the ocean. To truly determine if there was an ancient ocean on the Red Planet, we would need to send more missions to research the whole of Utopia Planitia
Wu, B., Dong, J., Wang, Y., Rao, W., Sun, Z., Krasilnikov, S., Li, Z., Tan, Z., Chen, Z., Wang, C., Ivanov, M., Zhu, J., Liu, W. C., Chen, L., & Li, H. (2024). A probable ancient nearshore zone in southern Utopia on Mars unveiled from observations at the Zhurong landing area. Scientific Reports, 14(1). https://doi.org/10.1038/s41598-024-75507-w
Related Articles