Read these three paragraphs from an article in today’s Times:
Using atomic clocks on Earth, the scientists measured the radio frequency with enough precision that they could discern changes in the velocity of Cassini [orbiting Saturn], hundreds of millions of miles away, as minuscule as 14 inches an hour.
They found that the moon’s [Enceladus, a moon of Saturn’s] gravity was weaker at the south pole. At first glance, that is not so surprising; there is a depression at the pole, and lower mass means less gravity. But the depression is so large that the gravity should actually have been weaker.
Liquid water is 8 percent denser than ice, so the presence of a sea 20 to 25 miles below the surface fits the gravity measurements.
The ingenuity involved in these calculations just amazes me. And it adds up to a big, important conclusion: tiny little Enceladus, all of 310 miles across, is definitively on the very short list of bodies in our solar system that are plausible candidates for extra-terrestrial life.
I hope I live long enough to witness dedicated missions to Titan, Europa and Enceladus that can determine conclusively whether life is present. Probably a long-shot for a 44 year old guy, given the inadequate pace of investment in big science. I’m more optimistic for Jeremy and Owen.