Vacation, Stay-cation, Mars-cation

Mars may have once boasted sunlit shores and rolling ocean waves, a far cry from the barren, dust-choked landscape we see today, according to a new study.

Data collected from China’s “Zhurong” rover showed evidence of underground rock formations in an area known as Utopia Planitia that resemble coastal deposits on Earth – hinting at strong evidence that a vast Martian ocean once existed.

“We’re finding places on Mars that used to look like ancient beaches and ancient river deltas,” said co-author Benjamin Cardenas in a statement. “We found evidence for wind, waves, no shortage of sand – a proper, vacation-style beach.”

The Zhurong rover, which landed in 2021 as part of China’s Tianwen-1 mission, was equipped with ground-penetrating radar that allowed it to scan beneath the red planet’s surface.

As it traversed 1.2 miles of terrain, the radar uncovered thick, sloping layers of material pointing toward a suspected ancient shoreline that looked identical to beach deposits found on Earth.

“The orientation of these features are parallel to what the old shoreline would have been,” Michael Manga, another study author, explained in a statement. “They have both the right orientation and the right slope to support the idea that there was an ocean for a long period of time to accumulate the sand-like beach.”

The findings suggest that water persisted on Mars for much longer than previously thought: Based on the thickness of the sediment layers, researchers estimated the ocean may have existed for millions of years, creating conditions that could have been favorable for microbial life.

“Shorelines are great locations to look for evidence of past life,” Cardenas noted. “It’s thought that the earliest life on Earth began at locations like this, near the interface of air and shallow water.”

The new study provides new insights into the decades-long debate as to whether Mars once had oceans.

NASA’s Viking orbiter images from the 1970s hinted at an ancient shoreline, but its uneven topography cast doubt on the idea. More recently, research has suggested that Mars’ massive Tharsis volcanic region may have shifted the planet’s rotation, distorting what was once a level shoreline.

But now, Zhurong’s data has provided direct underground evidence of preserved coastal deposits.

“This strengthens the case for past habitability in this region on Mars,” co-author Hai Liu of Guangzhou University said in a statement.