A free lunch? There's no such thing, of course. Something for nothing just doesn't happen.
But something from nothing, physicists are finding, may be the ultimate secret of the universe.
"The surprising fact is that we live in a universe that has all the characteristics of being created from nothing," says Arizona State University physicist Lawrence Krauss, author of this year'sA Universe from Nothing: Why There is Something Rather Than Nothing. "Science has made so much progress that we are having our faces pressed to the glass to see this reality."
Krauss is best known to readers from his bestseller, The Science of Star Trek, a physics treatise disguised as a book about a TV show. But among cosmologists, he has plied his trade as a theoretical physicist, pondering everything from the age of stars in our Milky Way galaxy to capturing nearly-undetectable "neutrino" particles zapped out of those stars.
A Universe from Nothingsums up in many way what has been Krauss's big focus — the big picture, or the character of the universe as a whole. In 1995, Krauss and University of Chicago physicist Michael Turner saw astronomical evidence converging on an idea discarded by Einstein, that a slight anti-gravitational force stretches the universe, increasingly pushing stars and galaxies farther away from one another.
You may have heard of this idea, called "dark energy," which most likely is what Krauss then called "vacuum" energy, a kind of force hidden away inside seemingly empty space. Last year's Nobel prize for physics went to astronomers Saul Perlmutter, Brian Schmidt and Adam Riess, who in 1998 observed that dark energy was increasing the distances between galaxies at an accelerating rate They measured this acceleration by observing how fast a particular class of exploding stars, so-called Type 1A supernova stars, appeared to be moving away from us. The farther away the supernova, the faster it seemed to be accelerating away, which was quite a surprise at the time. (Winning a Nobel Prize for research done only 13 years earlier is awfully soon. Some folks think too soon. Harvard-Smithsonian Center for Astrophysics physicist Yousaf Butt, for example, in a recent letter to Physics Today, argued that the supernova observations are too imprecise, and that other explanations exist for the acceleration, making the prize a hasty decision.)
Since 1998, cosmologists have seen supporting evidence for the accelerating expansion of the universe in more supernova observations, in raw measurements of the distances between distant galaxies, and in the Cosmic Microwave Background, a map of the heat leftover from the origin of the universe, the Big Bang, which took place about 13.72 billion years ago.
"Our hubris should be moderate, but there is a lot we do know now," Krauss says. Astronomers only figured out there was more to the universe than our Milky Way Galaxy less than a century ago, for example, and since then we have learned that more than 100 billion galaxies are out there, , he notes. "It is obvious now there was a beginning to the universe, and there does seem to be this vacuum energy. And it all seems to be tied to nothing." Of course, as his book explains, he adds: "A physicist's version of nothing is very different from what we once thought it was."
Nothing is something, it turns out, in physics. The equations that explain the innards of atoms produce so-called "virtual" particles that pop in and out of existence all the time on the sub-atomic level. These virtual particles cancel out each other at the end of the day, but in the meantime they lend atomic particles most of their mass. And their existence can be measured in electrical phenomena apparent at very small scales, such as the "Casamir" effect, observable as the attraction of two mirrors towards one another in a vacuum when placed very close together.
"We're like early mapmakers at this point," Krauss says, armed with a only few landmarks, such as the virtual particles. Although virtual particles can't add up to explain dark energy, his book says, they can explain the origin of the universe. Given a big enough emptiness, enough virtual particles can pop into existence, for free, to trigger a Big Bang and start a universe. "Nothing is doing something, and not only that. It has to do something," Krauss says.
If all this sounds a little philosophical, it might not be an accident. Forthrightly dubious of religion and theology, Krauss sees in the "something from nothing" result an answer to observers who see a need for a Creator to explain existence. That's a lot of folks, given that about four in 10 U.S. Gallup poll respondents feel that God created people about 10,000 years ago.
That's why he ended up doing the book, Krauss says, after a YouTube lecture (of course) on the origin of the universe went viral. "I really see a basic conflict between science and religion," he says. "I try not to be preachy, but I think it would be wonderful for the cultural debate if people saw what an amazing universe we live in, even if the evidence says it is likely an accident."