Mars was once a ‘blue planet’: Ancient river deltas point to vast ocean

Using images from cameras on Mars orbiters, an international research team has discovered structures on Mars that are very similar to classic river deltas on Earth. These are traces of rivers that have deposited their sediments into an ocean. This shows that Mars was a "blue planet" around 3 billion years ago.

Published: January 12, 2026 5:39 pm

Source: Phys.org — Read original