Evidence of ancient streambeds on Mars

Data from the Curiosity rover has shown evidence of ancient streambeds on Mars. The size, distribution, and shape of pebbles found in the area very closely resemble streambeds here on Earth.

From their calculations, the waters flowed about a meter per second and ranged from being ankle-deep to hip-deep. While the planet does have frozen water, this is the first evidence that it flowed in a liquid state for an extended period of time.

Photo credit: NASA/JPL-Caltech/MSSS