Mars appears to have long branching channels that have the appearance of being formed by a flowing liquid. Yet we know that liquids would not stay liquid in the very thin atmosphere we have on the Martian surface? So how can we explain the channels?1) they were made by wind-blown dust during the great Martian dust storms2) they are made by plate tectonics; by plates in the crust separating3) Mars may have had a thicker atmosphere long ago when the channels formed4) they were formed by volcanic lava from Olympus Mons5) the channels are artificial, made by a race of Martians that died out

Then try StudyFetch, the AI-powered platform that can answer your questions and teach you more about it!