Curiosity rover discovers ancient streambed on surface of Mars

The Curiosity rover is examining all sorts of things on the surface of Mars, but today, NASA is reporting a major breakthrough. Curiosity has discovered evidence on an old, dried up streambed on the surface of Mars, suggesting that water did once indeed flow on the Red Planet. Of course, we've seen evidence for the presence of water on Mars a few times in the past, but NASA scientists are calling this discovery "the first of its kind."

The big breakthrough here isn't the discovery of the channel – we've known about channels like this for a while now – but rather the discovery of gravel carried by the long-gone stream. The gravel is embedded in a conglomerate of rock, and it gives scientists a lot of information about the stream that once filled the channel. Curiosity science co-investigator William Dietrich says that the stream was likely flowing at three feet per second, "with a depth somewhere between ankle and hip deep."

Most of the gravel discovered by Curiosity is round in shape, which means that it traveled a significant distance. The conglomerate was discovered between the northern rim of the Gale crater and the base of Mount Sharp, which is where Curiosity will eventually end its two-year journey. The gravel likely came from above the rim, where the Peace Vallis channel feeds into an alluvial fan containing many other channels. NASA scientists say that the number of channels in the fan suggest that water was frequently flowing, which is a pretty big discovery.

The rounded shape of the gravel also confirms that the it was carried by water, not wind. NASA says that it might use Curiosity to examine the material holding the outcrop of rocks together as well as the composition of the gravel discovered embedded in the streambed. In doing so, it will give scientists a broader picture of the regional geography, and Mars Science Laboratory Project Scientist John Grotzinger says that NASA may have "already found our first potentially habitable environment," on the surface of Mars. That is definitely exciting, and we're looking forward to hearing more about Curiosity's mission soon. Stay tuned.

[via NASA JPL]