Its hard to believe that there was ever a time when I had not seen such an illustration before, but evidently I had not for I clearly remember being transfixed. I suspect, in honesty, my initial interest was based on a private image of streams of unsuspecting eastbound motorists in the American plains states plunging over the edge of a sudden 4,000-mile-high cliff running between Central America and the North Pole, but gradually my attention did turn in a more scholarly manner to the scientific import of the drawing and the realization that the Earth consisted of discrete layers, ending in the center with a glowing sphere of iron and nickel, which was as hot as the surface of the Sun, according to the caption, and I remember thinking with real wonder: How do they know that?
I didnt doubt the correctness of the information for an instant-I still tend to trust the pronouncements of scientists in the way I trust those of surgeons, plumbers, and other possessors of arcane and privileged information-but I couldnt for the life of me conceive how any human mind could work out what spaces thousands of miles below us, that no eye had ever seen and no X ray could penetrate, could look like and be made of. To me that was just a miracle. That has been my position with science ever since.
Excited, I took the book home that night and opened it before dinner-an action that I expect prompted my mother to feel my forehead and ask if I was all right-and, starting with the first page, I read.
And heres the thing. It wasnt exciting at all. It wasnt actually altogether comprehensible. Above all, it didnt answer any of the questions that the illustration stirred up in a normal inquiring mind: How did we end up with a Sun in the middle of our planet? And if it is burning away down there, why isnt the ground under our feet hot to the touch? And why isnt the rest of the interior melting-or is it? And when the core at last
burns itself out, will some of the Earth slump into the void, leaving a giant sinkhole on the surface? And how do you know this? How did you figure it out?
But the author was strangely silent on such details-indeed, silent on everything but anticlines, synclines, axial faults, and the like. It was as if he wanted to keep the good stuff secret by making all of it soberly unfathomable. As the years passed, I began to suspect that this was not altogether a private impulse. There seemed to be a mystifying universal conspiracy among textbook authors to make certain the material they dealt with never strayed too near the realm of the mildly interesting and was always at least a long-distance phone call from the frankly interesting.
I now know that there is a happy abundance of science writers who pen the most lucid and thrilling prose-Timothy Ferris, Richard Fortey, and Tim Flannery are three that jump out from a single station of the alphabet (and thats not even to mention the late but godlike Richard Feynman)-but sadly none of them wrote any textbook I ever used. All mine were written by men (it was always men) who held the interesting notion that everything became clear when expressed as a formula and the amusingly deluded belief that the children of America would appreciate having chapters end with a section of questions they could mull over in their own time. So I grew up convinced that science was supremely dull, but suspecting that it neednt be, and not really thinking about it at all if I could help it. This, too, became my position for a long time.
Then much later-about four or five years ago-I was on a long flight across the Pacific, staring idly out the window at moonlit ocean, when it occurred to me with a certain uncomfortable forcefulness that I didnt know the first thing about the only planet I was ever going to live on. I had no idea, for example, why the oceans were salty but the Great Lakes werent. Didnt have the faintest idea. I didnt know if the oceans were growing more salty with time or less, and whether ocean salinity levels was something I should be concerned about or not. (I am very pleased to tell you that until the late 1970s scientists didnt know the answers to these questions either. They just didnt talk about it very audibly.)
And ocean salinity of course represented only the merest sliver of my ignorance. I didnt know what a proton was, or a protein, didnt know a quark from a quasar, didnt understand how geologists could look at a layer of rock on a canyon wall and tell you how old it was, didnt know anything really. I became gripped by a quiet, unwonted urge to know a little about these matters and to understand how people figured them out. That to me remained the greatest of all amazements-how scientists work things out. How does anybody know how much the Earth weighs or how old its rocks are or what really is way down there in the center? How can they know how and when the universe started and what it was like when it did? How do they know what goes on inside an atom? And how, come to that-or perhaps above all-can scientists so often seem to know nearly everything but then still cant predict an earthquake or even tell us whether we should take an umbrella with us to the races next Wednesday?