Theorists have come up with all sorts of possibilities in an attempt to reconcile general relativity with quantum mechanics: parallel universes, colliding universes, bubble universes, universes with extra dimensions, universes that eternally reproduce, universes that bounce from Big Bang to Big Crunch to Big Bang.
Adam Riess, an astronomer who collaborated with Brian Schmidt on the discovery of dark energy, says he looks every day at an Internet site (xxx.lanl.gov/archive/astro-ph) where scientists post their analyses to see what new ideas are out there. “Most of them are pretty kooky,” he says. “But it’s possible that somebody will come out with a deep theory.”
For all its advances, astronomy turns out to have been laboring under an incorrect, if reasonable, assumption: what you see is what you get. Now astronomers have to adapt to the idea that the universe is not the stuff of us—in the grand scheme of things, our species and our planet and our galaxy and everything we have ever seen are, as theoretical physicist Lawrence Krauss of Arizona State University has said, “a bit of pollution.”
Yet cosmologists tend not to be discouraged. “The really hard problems are great,” says Michael Turner, “because we know they’ll require a crazy new idea.” As Andreas Albrecht, a cosmologist at the University of California at Davis, said at a recent conference on dark energy: “If you put the timeline of the history of science before me and I could choose any time and field, this is where I’d want to be.”
Richard Panek wrote about Einstein for Smithsonian in 2005. His book on dark matter and dark energy will appear in 2011.