If the northern lowlands of Mars were filled with water, approximately how much of the planet's surface could this ancient ocean have covered?

Answer

Up to a third of the planet's surface

The text suggests that if the significantly lower northern lowlands were filled, the resulting ancient ocean could have covered up to a third of the planet's surface, implying a global hydrological cycle.

If the northern lowlands of Mars were filled with water, approximately how much of the planet's surface could this ancient ocean have covered?

#Videos

Just in: NASA Has Found Oceans of Liquid Water on Mars...For Real

MarsSpaceGeologywaterevidence