Mars may once have had an ocean with sandy beaches, radar data suggests
GuardianFEB 26
Study: Mars Had 'Vacation-Style' Beaches
Above: A model of China's Mars rover Tianwen-1 at the InnoTech Expo on Dec. 12, 2022, in Hong Kong, China. Image copyright: NurPhoto/Contributor/NurPhoto via Getty Images
The Facts
Using ground-penetrating radar data, China's Zhurong rover discovered evidence of ancient beaches buried beneath Mars' surface — revealing sedimentary deposits sloping downward at angles between 6 and 20 degrees, extending northward for about 1.3 km (0.8 miles).
The buried structures, found in the southern Utopia Planitia region, show similarities to Earth's coastal deposits, with multiple parallel layers indicating the presence of tides and waves that transported sediments for tens of millions of years.
The scientists identified 76 subsurface dipping reflectors at depths between 10 to 35 m (32.8 ft to 98.4 ft), with an average dip angle of 14.5 degrees, similar to Earth's beach formations and suggesting a stable, long-lasting body of water rather than temporary melt events.
The Spin
Narrative A
This study bolsters the theory that Mars could host life by suggesting water lasted into the Late Hesperian, enhancing habitability. It also aligns with a Brown University study showing that Mars' red color comes from water-rich ferrihydrite, which points to a wet past. Evidence from Martian meteorites (4.5B years ago) and recent ice-filled craters further imply that Mars contained life-supporting conditions for longer than previously thought.
Narrative B
We shouldn't get too excited about finding liquid water on Mars soon. While ripple marks do show ancient lakes existed billions of years ago, Mars' lost magnetic field let solar winds strip its atmosphere and water, leaving a cold desert. Another recent study also placed doubt on liquid brines holding water, citing sand flows and harsh conditions. Ice, not liquid, dominates on Mars.
Cynical narrative
Mars shouldn't dominate so much scientific focus. Its weak gravity thwarts terraforming, offering scant technological gain, while space stations outshine it for habitation tech. Asteroid mining will also outperform Mars' costly resource extraction, while Earth's deserts and oceans provide cheaper testing grounds. After decades of research, Mars has proven insufficient as an alternative to Earth.
Metaculus Prediction
The Controversies
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