One of the objectives for NASA’s Curiosity rover is to determine whether Mars ever could have supported life. While Curiosity hasn’t run across any little green men, it has discovered evidence that running water once flowed across the planet’s surface: the remains of a Martian streambed.
It’s a discovery that would probably put a smile on the face of Giovanni Schiaparelli, the 19th century Italian astronomer who first observed and described Mars’ so-called “canals.” He may have been a little off target, but this is further evidence that Mars wasn’t always the dry world it is now. NASA scientists are examining the gravel and stones found in the dry streambed, which can reveal quite a lot about the stream’s history. William Dietrich, one of Curiosity’s co-investigators from the University of California, explains:
From the size of gravels it carried, we can interpret the water was moving about 3 feet per second, with a depth somewhere between ankle and hip deep. Plenty of papers have been written about channels on Mars with many different hypotheses about the flows in them. This is the first time we’re actually seeing water-transported gravel on Mars. This is a transition from speculation about the size of streambed material to direct observation of it.
And while discovering evidence like this is exciting in and of itself, NASA scientists believe it could also mean they’re on the right track in their search for once-habitable locations that could hold evidence of Martian life – assuming there’s any to find. “A long-flowing stream can be a habitable environment,” says Mars Science Laboratory Project Scientist John Grotzinger of the California Institute of Technology in Pasadena. “It is not our top choice as an environment for preservation of organics, though. We’re still going to Mount Sharp, but this is insurance that we have already found our first potentially habitable environment.”
Whether Curiosity ever finds evidence of ancient or current microbial life on Mars, it’s already making worthwhile discoveries. Here we are in front of our computers, staring at what used to be a flowing stream on the surface of Mars, beamed back by a robot the size of a car. How cool is that?