Some legal folk are accustomed to distinguishing between the hard sciences and the soft sciences. But if the truth be known, even the hardest of sciences have soft ingredients. Consider, for example, the methods now being used to search for earth-like planets whirling around other stars:
Dennis Overbye, Gazing Afar for Other Earths, and Other Beings NYTimes (January 30, 2011):
There is a hitch to confirming those planets, however. Such planets would not exert enough of a gravitational tug on their suns to be detectable by the “wobble” method, the main way their masses can be measured. Instead of confirming such planets, Kepler astronomers talk about “validating” them by using high-powered telescopes to make sure, for example, that there is only one star there and not a pair of eclipsing stars or some other phenomenon that could mimic a planet’s shadow.
“Earths are difficult,” Mr. Borucki said. “We’re concerned not to announce anything until we’ve proven six different ways it can’t not be a planet.”
As a result, more and more of Kepler’s future pronouncements will be statistical in nature. Natalie Batalha of San Jose State University, the deputy science team leader for Kepler, said it could be that they will wind up with, say, 100 planets they are 80 percent sure of, which could translate to 80 planets — useful for a census, not so helpful if you’re looking for a place to live.
“It’s a bitter pill to swallow,” said Sara Seager, an M.I.T. planetary astronomer who works with Kepler. “We will be faced with hundreds of planet candidates that may never be fully vetted as planets. We just have to live with statistics.”