‘Smoking gun’ for universe’s expansion reported found by astronomers

A team of scientists from the Harvard-Smithsonian Center for Astrophysics announced a 'major discovery' today, as their research shows what they're calling the first detection of gravitational waves and the first direct evidence for inflation — the rapid expansion that our universe underwent starting just moments after it was born.

Around 13.8 billion years ago, at a trillionth of a trillionth of a trillionth of a second after the Big Bang, our tiny fledgling universe suddenly began expanding at an incredible rate. Scientists have been able to detail this 'inflation' on paper and in computer models, and they've known what to look for when trying to find actual evidence of it — specifically a phenomenon predicted by Einstein called gravitational waves — but so far the signs have remained elusive.

However, a team of researchers led by the Harvard-Smithsonian Center for Astrophysics (CfA) have used the South Pole Telescope in Antarctica to scan the Cosmic Microwave Background (CMB) — the leftover radiation from the Big Bang — with very sensitive instruments. They gathered data for years, and then spend three years afterward carefully examining their findings to rule out errors and search for patterns. When they were done, the team picked out swirls in the polarization pattern of the radiation, which are shown by the colours and black lines in the image below:

After exploring other possibilities for the pattern, like the influence of galactic dust, they are confident that these swirls are the evidence of gravitational waves that they have been hoping to find.

"Detecting this signal is one of the most important goals in cosmology today. A lot of work by a lot of people has led up to this point," John Kovac, the CfA astrophysicist who led the BICEP2 collaboration that made the discovery, said in a statement.

This video from Nature details the whole idea behind the discovery quite nicely:

"This is a totally new, independent piece of cosmological evidence that the inflationary picture fits together," theoretical physicist Alan Guth of the Massachusetts Institute of Technology (MIT) in Cambridge, told Nature. Guth was the first to propose the idea of inflation, back in 1980.

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The research being announced today hasn't been submitted to science journals, so it hasn't been verified by other members of the scientific community. That means that we should remain skeptical of it for now, but some cosmologists, like Marc Kamionkowski, from Johns Hopkins University in Baltimore, Maryland, are already saying that the data looks solid.

Avi Loeb, a pioneering astrophysicist at the CfA, who was not part of the BICEP2 collaboration, said in a CfA statement, "This work offers new insights into some of our most basic questions: Why do we exist? How did the universe begin? These results are not only a smoking gun for inflation, they also tell us when inflation took place and how powerful the process was."

If the studies weather the scrutiny they're going to be put under, it will give scientists a definitive look at what the very early universe was like. Also, since quantum physics dominated the universe at that very early stage, showing that gravitational waves were generated at the time would have gravity joining the other fundamental forces — strong nuclear, weak nuclear and electromagnetic — as a quantum phenomenon. That would link together quantum mechanics and general relativity, which are two of the most important theories we have about how our universe works.

(Images courtesy: NASA/WMAP, BICEP2 Collaboration)

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