At The New Yorker, physicist Lawrence Krauss gives his take on the recent direct evidence that cosmic inflation is real. Money quote:
At rare moments in scientific history, a new window on the universe opens up that changes everything. Today was quite possibly such a day. At a press conference on Monday morning [March 17, 2014] at the Harvard-Smithsonian Center for Astrophysics, a team of scientists operating a sensitive microwave telescope at the South Pole announced the discovery of polarization distortions in the Cosmic Microwave Background Radiation, which is the observable afterglow of the Big Bang. The distortions appear to be due to the presence of gravitational waves, which would date back to almost the beginning of time.
This observation, made possible by the fact that gravitational waves can travel unimpeded through the universe, takes us to 10-35 seconds after the Big Bang. By comparison, the Cosmic Microwave Background—which, until today, was the earliest direct signal we had of the Big Bang—was created when the universe was already three hundred thousand years old.
If the discovery announced this morning holds up, it will allow us to peer back to the very beginning of time—a million billion billion billion billion billion times closer to the Big Bang than any previous direct observation—and will allow us to explore the fundamental forces of nature on a scale ten thousand billion times smaller than can be probed at the Large Hadron Collider, the world’s largest particle accelerator. Moreover, it will allow us to test some of the most ambitious theoretical speculations about the origin of our observed universe that have ever been made by humans—speculations that may first appear to verge on metaphysics. It might seem like an esoteric finding, so far removed from everyday life as to be of almost no interest. But, if confirmed, it will have increased our empirical window on the origins of the universe by a margin comparable to the amount it has grown in all of the rest of human history. Where this may lead, no one knows, but it should be cause for great excitement.
And here’s a bit more from Krauss:
Even for someone who has been thinking about these possibilities for the past thirty-five years, the truth can sometimes seem stranger than fiction. In 1979, a young particle physicist named Alan Guth proposed what seemed like an outrageous possibility, which he called Inflation: that new physics, involving a large extrapolation from what could then be observed, might imply that the universe expanded in size by over thirty orders of magnitude in a tiny fraction of a second after the Big Bang, increasing in size by a greater amount in that instance than it has in the fourteen billion years since. […]
[O]n Monday, [a] probe of the microwave background—one that measures how the light generated at the time the C.M.B. was created might be “polarized,” as space is alternatively compressed and stretched by gravitational waves—apparently sees precisely the signal expected from Inflation. Moreover, the amplitude of the effect is indeed more or less expected if the scale of Inflation is the scale expected for Grand Unification.
And what’s one of the key implications of this discovery? Krauss explains:
If it turns out to be confirmed by other experiments, think about what this discovery implies for our ability to explore the universe (besides the other remarkable implications for physics): when we use light to look out at the distant universe, we can only see back as far as three hundred thousand years after the Big Bang, when the universe cooled sufficiently to become transparent to light. But gravitational waves interact so weakly that even waves produced less than 10-35seconds after the Big Bang can move through space unimpeded, giving us a window on the universe at essentially the beginning of time.
And what about God? Here’s Krauss one last time:
For some people, the possibility that the laws of physics might illuminate even the creation of our own universe, without the need for supernatural intervention or any demonstration of purpose, is truly terrifying. But Monday’s announcement heralds the possible beginning of a new era, where even such cosmic existential questions are becoming accessible to experiment.
There are lots of logically possible ways that the cosmos could have been at the beginning of creation, but there is only one way that the cosmos actually was. Science is closing in, by experiment, on what that was. In comparison with arm chair metaphysics and theology, science shows us the money.