NASA Mars Rover Curiosity Discovers Evidence for Ancient Streambed and Flowing Water

When NASA's Mars rover Curiosity landed on the Red Planet last year, it immediately began seeking out samples and signs of life. Now, researchers have started to interpret the data that Curiosity has collected and have made some unusual finds. They've discovered that the pebble-containing slabs that the rover investigated last year are part of an ancient streambed.

The pavement-like rocks were first examined with the telephoto capability of Curiosity's Mast Camera (Mastcam) during the rover's first 40 days on the surface of the planet. One particular rock, named "Goulburn," is right next to the rover's "Bradbury Landing" touchdown site. The other two, "Link" and "Hottah," are a few hundred feet to the southeast. In addition to just looking at the rocks, the rover also used the laser-shooting Chemistry and Camera (ChemCam) to investigate Link.

"These conglomerates look amazingly like streambed deposits on Earth," said Rebecca Williams of the Planetary Science Institute in a news release. "Most people are familiar with rounded river pebbles. Maybe you've picked up a smoothed, round rock to skip across the water. Seeing something so familiar on another world is exciting and also gratifying."

When the researchers further studied the images that Curiosity collected, they found some specific details about the area. The larger pebbles weren't distributed evenly in the conglomerate rocks. In Hottah, researchers detected alternating pebble-rich layers and sand layers--very common in streambed deposits on Earth. In addition, many of the pebbles touched each other, which indicated that they rolled along the bed of a stream.

"We ended up with a calculation in the same range as our initial estimate last fall," said Williams in a news release. "At a minimum, the stream was flowing at a speed equivalent to a walking pace-a meter, or three feet, per second-and it was ankle-deep to hip-deep."

The findings have huge implications for the study of Mars. Currently, the atmosphere of modern Mars is too thin to make a sustained stream flow of water possible, despite its large deposits of water ice. These recent findings hint at a planet that may have had diverse environments in the past--and possibly a different atmosphere. It's also hints that even if life doesn't currently exist on Mars, it may have done so in the past.

The findings are published in the journal Science.