The Chinese Rover sent back some extraordinarily interesting information about possible sandy beaches on Mars. Photo: CNSA
China’s Zhurong Rover, a little vehicle that trekked around Mars for a year starting in May, 2021, revealed something pretty incredible: evidence of what sure seems to be sandy beaches that once edged a large ocean.
It’s a relatively sure thing that Mars did indeed once have water. The hypothesized ocean likely existed around 3.5 to four-billion years ago, when Mars was a warmer and wetter place than it is today. We named the ancient ocean Deuteronilus — which, I assume, is named after Deuteronomy, the fifth book in the Torah in which Moses delivered rousing speeches to the Israelites on the Plains of Moab — and if it did exist, it took up much of Mars’ northern plains.
The idea that Mars had lots of water once upon a time opens up a million possibilities. Life as we know it came from the Earth’s primordial oceans, and scientists think that a martian ocean could once have played host to alien life.
The Chinese rover spent a year bumping around Mars, using ground-penetrating radar to figure out what’s going on deep below the Red Planet’s current day surface. According to a report in the Proceedings of the National Academy of Sciences (which uses the unfortunate acronym of PNAS), between 33-115 feet down, the rover found layers of a material very similar to sand. All of it sloped in the same direction, like our beaches slope down towards the sea. After inspecting the data, researchers were able to map out what looks to be an ancient martian shoreline.
“The martian surface has changed dramatically over 3.5 billion years,” said Guangzhou University’s planetary scientist Hai Liu, “but by using ground-penetrating radar we found direct evidence of coastal deposits that weren’t visible from the surface.”
Here on our Pale Blue Dot, beaches take millions of years to form. Waves need to crash endlessly on shores to form sand, and if Mars is anything like Earth, that’s likely also the case. Wave action and rivers flowing from mountains and tides probably all existed there, and probably existed for millions of years. And with oceans come life.
“The beaches would have been formed by similar processes to those on Earth — waves and tides,” Liu explained. “Such oceans would have profoundly influenced Mars’ climate, shaped its landscape and created environments potentially suitable for life to emerge and thrive.”
Shorelines, according to Michael Manga, a planetary scientist at the University of California, Berkeley, are fantastic places to find evidence of extinct life.
“It’s thought that the earliest life on Earth began at locations like this,” he said, “near the interface of air and shallow water.”
Since Mars is, to put it mildly, very far away, it’s tough to be 100 percent sure of any theories. The Deuteronilus Ocean theory, however, has passed quite a few tests that could be considered near-proof of existence.
“A primary part of this work was testing these other hypotheses,” Penn State geoscientist and study co-author Benjamin Cardenas told Reuters. “Wind-blown dunes were considered, but there were a few issues. First, dunes tend to come in groups, and these groups produce characteristic patterns not present in these deposits. We also considered ancient rivers, which exist in some nearby locations on Mars, but we rejected that hypothesis for similar reasons based on the patterns we saw in the deposits. And you don’t typically get structures like this in lava flows, either. Beaches simply fit the observations the best.”
