The salts they found are like salts found in Earth's oceans. The findings suggest a uniformity between the planets Earth and Mars. Water channels seen previously. Hundreds of long, winding channels on Mars look like dried-up rivers. In fact, they look like stream beds cut by sudden runoff in desert regions on the Earth.
Astronomers see the channels as evidence of liquid water erosion.
Lava and glacial erosion would have produced very different channels. If so, the channels also are evidence that the climate on Mars has changed dramatically. Of course, liquid water cannot exist on Mars today. If any buried water reached the surface, the planet's low atmospheric pressure would boil it to a vapor. Once in the atmosphere, the water vapor would circle the poles and freeze out.