Laurence Krauss in The New Yorker:
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 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.