Only a few years ago Stephen Hawking, the famous British physicist, was confident enough about his theories to remark that the next couple of discoveries would unveil "the face of God." He meant that the secrets of the universe's origin and nature would be completely revealed.
Well, back to the blackboard, Dr. Hawking.
Recent findings from the Hubble space telescope have thrown cosmology into crisis: 90 percent of the universe isn't there. And some of the stars are twice as old as the universe of which they are a part.
One reason for Dr. Hawking's optimism was that astronomers could now see to the edge of the universe and observe stars practically in the process of birth. By measuring how far away the stars were, and knowing how long light travels to reach our eyes, scientists could know how old the stars were. By comparing distant, older stars to nearer, younger ones, they could make pretty good guesses about the life cycle of stars, and how long the whole process has been going on.
And now Hubble tells us the older stars have been around for 16 billion years or so, but the universe itself is only 8 to 12 billion years old. How can that be? Where were the stars before there was a universe? In Hollywood?
Scientists have known for 60 years that there wasn't enough matter in the universe to hold it together, but it didn't worry them. The rest of the universe, they figured, was out there but invisible. "Dark matter," they called it -- probably small red dish stars too dim to see with our telescopes.
But now Hubble has peered at the places where there seems to be more gravity than matter -- places where dark matter is supposed to make up the difference. And there is no dark matter, or else it's even darker than we thought.
So it's back to the calculator. There's anti-matter, with negative protons and positive electrons, so maybe there's anti-gravity, too. Maybe there's some other kind of matter we don't know about -- call the particles "axions" and "WIMPs" (for weakly interacting massive particles). Maybe there's "weird exotic stuff . . . all around us right now," speculates David Schramm, a University of Chicago astrophysicist.
"It's embarrassing for astronomers to admit we can't find 90 percent of the matter in the universe," sighs Bruce Margon, of the University of Washington.
The search is on for some way to save the theory -- or for a new theory. We go through this every millennium or so.
The great second-century astronomer, Ptolemy, devised a cosmos of nesting spheres, like a Russian Matryoshka doll. The kernel at the center was the earth, around which a succession of spherical shells carried sun, moon, planets and stars. It was a pretty good theory; for more than a thousand years Ptolemy's tables predicted eclipses and guided navigators.
As measuring techniques got better, though, inelegance began to gnaw at the Ptolemaic universe. The planets, and even some stars, seemed to wobble as they made their stately progressions across the vault of heaven. Astronomers proposed solutions that would save the theory: Maybe the planets were describing circles, or epicycles, around the paths of their orbits. That helped some, but not completely. Maybe the epicycles around the orbits had secondary epicycles of their own.
Eventually, unwieldiness doomed Ptolemy's theory, along with two radical insights: Even though circles were magical, planets didn't have to move in circles; they could make ellipses. And if the earth moves instead of standing still, then the shifting perspectives from earth would account for the apparent wobbles in planetary motion.
The crashing of Ptolemy's universe was greeted with rude mockery by the uneducated to whom plain common sense made it clear that the sun moves around the earth, not vice-versa. Intellectuals could understand the new theory, and it devastated them. John Donne wrote a poem in which he likened the death of a friend's daughter to the end of a comprehensible universe: " 'Tis all in peeces, all cohaerence gone."
WIMPs and anti-gravity may be this generation's epicycles, something dreamed up to save the theory. You don't junk a good theory lightly, and the physics we have now worked well enough to get the Hubble aloft, after all.
But it may be instead that more than WIMPs we need a new Copernicus to find the rest of the universe.
Hal Piper edits The Sun's Opinion * Commentary page.