[537 Votes]

As long ago as the 1970s, people were looking at the first topographic maps of Mars and noticing that the terrain in the northern hemisphere was smoother than the terrain in the southern hemisphere, and that the dividing line between terrains looked remarkably like a dried, ancient coastline.

That would imply, of course, that half of the Martian surface was once covered by an ocean. Mars was a water world without any question.

IMO, NASA is simply trying to make PR points by proving and reproving something which was proven to most intelligent people's satisfaction long ago.

[SedVictaCatoni]

IMO, NASA is simply trying to make PR points by proving and reproving something which was proven to most intelligent people's satisfaction long ago.

To be fair, it is possible that we simply don't understand enough about areology to determine whether we're looking at a coastline or a merely a different kind of wind erosion pattern than we have here on Earth. Many intelligent people once looked at the water channels on Mars, looked at canals on Earth, and drew a conclusion to their satisfaction.