The 4% Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality

by Richard Panek

Other theorists—Andrei Linde, at the Lebedev Physical Institute in Moscow, and, independently, Paul Steinhardt and Andreas Albrecht, at the University of Pennsylvania—identified the problem and found the solution. They reconceived the inflationary period to be, as Guth came to think of it, less like the bubbling of boiling water than the congealing of a single Jell-O bubble. The problem with the one-bubble inflationary model, however, was that it still had to account for the visible universe—homogeneous and isotropic, but not too homogeneous and isotropic, or else we wouldn’t be here. They were all borrowing from Hawking. In 1973 Hawking had redefined the study of the early universe with his work on black holes; he found that, owing to a combination of quantum and gravitational effects, they weren’t one-way tickets to a singularity. At the edge of the event horizon—the black hole’s ring of no return—quantum effects dictated that particles and antiparticles would be popping into existence, while gravitational effects dictated that one partner would disappear into the black hole but not the other. Rather than annihilating each other “immediately,” one would slip over the edge, into the black hole, but the other would escape into space and the universe as we know it. Black holes, Hawking contended, aren’t black after all. They leak radiation—Hawking radiation, as it came to be called. In effect, Hawking had begun to bridge the two seemingly irreconcilable theories of the twen...