NASA’s spacecraft have taken pictures of tens of thousands of those lakes out of orbit, and once rover Curiosity landed in 2012, it was sent back pictures of pebbles which were curved, campaigning for a quite long time in the bottom of a river. It’s a puzzle why early Mars had liquid water, researchers stated. Mars has a very lean air today, and early in the planet’s history, it was only receiving a 3rd of the sun of the present Earth, which should not be sufficient heat to keep liquid water. Really, on old Mars, when it was wet enough for rivers a few of the time, the rest of the data looks like Mars was cold and dry more often than not, Kite said. Seeking a better knowledge of Martian precipitation, researchers lacked photos and elevation models for over 200 early Martian riverbeds spanning more than a billion years.
These riverbeds are a rich source of hints about the water flowing through them and the climate which generated it. For instance, the width and abruptness of the riverbed and the size of the gravel tell scientists about the power of the water stream, and the amount of gravel limits the amount of water passing through. Their investigation shows clear evidence for persistent, strong runoff that happened well into the last phase of the wet climate, Kite said. The results provide guidance for all those attempting to rebuild the Martian climate, he said.