Mars may have hosted a vast ancient ocean, researchers propose
NASA-backed simulations suggest Mars may have once been largely covered by an ocean, potentially about one-third of the planet, leaving behind a broad, flat coastal shelf around where shorelines would have been. Using Earth analogs and Mars Orbiter Laser Altimeter data, researchers say this signature—larger and more durable than a shoreline—could indicate a past ocean, though the lack of plate tectonics on Mars makes the case not definitive. If confirmed, the coastal shelf would provide a tangible target for future observations, including ESA's Rosalind Franklin rover, to help explain Mars' wetter past and its water loss.
