Mars Rover Finds Ancient Streambed—Proof of Flowing Water
NASA pictures offer unprecedented on-ground evidence: telltale pebbles, gravel.
Scientists announced Thursday that water—fast-running and relatively deep—once coursed over the now bone-dry surface, a finding based on the presence of rounded pebbles and gravel near the rover's landing site in Gale Crater.
What's more, the team has concluded that the water was present for "thousands or millions of years," though the researchers said it would take far more research to get a clearer picture of the flow's longevity.
The discovery is the first proof that surface water once ran on Mars. Planetary scientists have hypothesized that the cut canyons and riverlike beds photographed by Mars satellites had been created by running water, but only now do researchers have on-the-ground confirmation—and the promise of learning much more about the nature and duration