This column first ran in The Tablet in October, 2006.
Doing science has often been compared to reading a mystery novel; the hunger to know “whodunit” keeps us turning the pages. But what stops us from just skipping to the last page, and moving on to the next book? Perhaps a better metaphor is a spice cake. The real pleasure of the process lies in the spicy experience of wondering. Actually finding out is just the icing on the cake.
At the annual meeting of the Division for Planetary Sciences (DPS) of the American Astronomical Society, held earlier this month in Pasadena, California near the famed Jet Propulsion Laboratory (JPL), dozens of little slivers of spice cake were on offer.
A wonderful little asteroid system, called 1999 KW4, passed within half a million kilometers of the Earth about five years ago; it’s taken that long to analyze the radar reflections and work out its remarkable shape and spin. It’s shaped like a top, with a ridge about its equator that looks like a mountain range. But in fact it is spinning so quickly that dust on its surface slides “uphill” to the top of these mountains, where it is only just balanced by the asteroid’s gravity against being flung out into space. The icing, the bit that proves the hypothesis? This little asteroid has a moonlet, as you’d expect for material spun off its parent.
Outside Saturn’s more famous rings, earlier spacecraft had discovered a fainter ring where the moon Enceladus orbits. Where did the material in this ring come from? The subject has tantalized theorists for twenty years. Now the Cassini spacecraft has found fountains of liquid water pouring out from Enceladus’ south pole.
Previous images of Ceres, the largest asteroid, showed a shape that suggested it was a differentiated body with a rocky core, icy mantle, and dark rock crust. Is Ceres actually another geologically active dwarf planet, like Pluto? The icing: new Hubble infrared images now indicate a surface covered with suggestive looking features. (And of course, we now know ever so much more about Ceres... with ever so many more questions!)
We got a bit of icing on our own spicy puzzle, described in my column here about a cloud of gas we’d observed moving away from a Centaur, orbiting in from beyond Neptune en route towards the Sun. Our colleagues at JPL now suggest that we were watching a separate comet, one that almost shares an orbit with the Centaur, and the two just happened to be passing near each other when we observed them last spring. They encounter each other only occur once every 1600 years; we were just lucky.
Like spice cake, each one of these explanations leaves us hungry for more. What makes the asteroid spin so fast? Why does only Enceladus have fountains? Are those features on Ceres geology, or just impact craters? And, just as nerve-wracking: how will the upcoming US Congressional elections affect the NASA research budget to find out these answers?
We don’t know the answers to any of those questions. But the suspense, the spice, is made bearable by the faith that the answers will come... with luck, on a time scale not too painfully distant.
That faith is what keeps us going through all the uncertainties of daily life, including the biggest questions of all — the ones we won’t solve until our lives here have ceased. But just as each newly solved science puzzle generates ever more bits of spice, it seems to be a pattern of the universe that even “the end” will be no end at all, just the introduction to a newer tantalizing experience.
Indeed, it was only by solving previous mysteries that these delicious news ones have come to light. A scientific answer that doesn’t suggest new problems is as cloying as icing without cake. In life, as in science, you can only have your cake by eating it.