When I was a kid, my dad taught me the science of skippingstones. There on the rocky banks of a little stream behind our house inHuntingdon Valley, Pennsylvania, he coached me not only on the proper pitchingmotion, but on the significance of the right equipment. While the throw wasimportant, it was the stone itself that held the secrets to a good skip.Recently, we have found stones just like the best skippers “ 180 million milesaway from Huntingdon Valley. These stones are on Mars.
As the chief scientist for NASA’s Curiosity Mars rover,locating such a smooth and flat rock on the Red Planet means water once flowedthere “ and nothing could be more important. It means that we sent ourplutonium-powered, SUV-sized, six-wheeled, science-instrumented vehicle to theright place.
Getting early confirmation that we came to the right placeis a huge deal “ and it has come early in the mission. We landed Curiosity onAugust 5 on a place on Mars called Gale Crater.
Working the data we have received so far, we believe thewater source that propelled our skipping stone to its present location wasanywhere from ankle to hip-deep and flowed at about 3 feet per second. Thedistance traveled and the source of the water is unknown, but in my mind’s eyeI can picture the different scenarios that could bring that little stone intoexistence. And to a planetary geologist, each and every one of them has its owninner and outer beauty. Perhaps one day, our insatiable Curiosity will help uslearn which of these scenarios is correct.
In the meantime, we’ve put our skipping stones in therover’s rearview mirror (several of our 17 cameras watched them disappear overthe horizon) and moved forward in both time and space.
Just the other day, we crossed another significant thresholdof the mission by processing our first sample of Mars in one of Curiosity’sonboard chemistry labs. Essentially, we’re eating dirt and loving it. With thisstep, we’ve begun doing the kind of exacting scientific research you wouldusually only be able to accomplish in a fully stocked laboratory at a universityor research center. Now, we’re doing it on Mars.
What these findings will tell us we’re not sure. But we doknow that Gale Crater, the skipping stones and the baby aspirin-sized sample ofMartian dirt the rover just ingested all have a story to tell.
Norman Maclean wrote in his seminal work, “A River RunsThrough It and Other Stories”: “Eventually, all things merge into one, and ariver runs through it. The river was cut by the world’s great flood and runsover rocks from the basement of time. On some of the rocks are timelessraindrops. Under the rocks are the words, and some of the words are theirs. Iam haunted by waters.”
I imagine that the pursuit of this clear liquid and thestories and worlds it helps recreate will go on well beyond our rover’smission. That someday, an astronaut may very well walk in the treaded footstepsof Curiosity and find these stones or ones like them. When that day happens,180 million miles away from home, in Gale Crater or elsewhere on the planet ofMars, for at least a moment, they might think back to their own simpler timewhen, on the shoreline of some body of water, they first learned the value ofthe perfect stone.
Then, I imagine, they’ll get back to work because on Marsthere is a lot to see, a lot to do, and a lot to learn.
John Grotzinger is the project scientist for the MarsScience Laboratory mission
