Evidence: Ancient Mars may have had oceans

3039132272_4fedf1accc_o Saying the issue is how long, not whether, Mars had water, the Bad Astronomer himself, Phil Plait, goes on to suggest that the issue has relevance for our own planet:

It may have once been much more Earth-like, but then something went wrong. Maybe it was the formation of the giant volcanoes (indicated by the red arrows in the above image), or the loss of its magnetic field that exposed its atmosphere to erosion by the solar wind. As we study Mars more, we get closer to figuring this out. And make no mistake: knowing where Mars went wrong gives us great insight into our own planet. If you think we’re wasting money on researching Mars, then I suggest you take a cold, hard look at that cold, hard planet, then look out your window at our own home world.

The news is here. Seas, perhaps, in the areas of this picture where red and yellow predominate.

Image credit: University of Arizona