Since 1991, planetary scientists have floated the idea that Mars once harbored vast oceans that covered roughly one-third of the planet. Two long shore-like lips of rock in the planet’s northern hemisphere were thought to be the best evidence, but experts argued that they were too “hilly” to describe the smooth edges of ancient oceans.
The view just changed dramatically with a surprisingly simple breakthrough.
The once-flat shorelines were disfigured by a massive toppling over of the planet, scientists announced today. The warping of the Martian rock has hidden clear evidence of the oceans, which in any case have been gone for at least 2 billion years.
