Gravitational Waves From Just After Big Bang Show How Universe Grew
By Amina Khan, Los Angeles Times
Nearly 14 billion years ago, in a tiny fraction of a second after the Big Bang, the universe suddenly expanded from smaller than an atom to 100 trillion trillion times its original size, faster than the speed of light. This mysterious period, known as cosmic inflation, had been theorized but never confirmed.
But now, scientists using telescopes at the South Pole say they have discovered the first direct evidence for this incredible growth, in the signature of gravitational waves.
“It’s amazing,” said experimental cosmologist John Carlstrom of the University of Chicago, who leads the competing South Pole Telescope project. “Everyone in my field, what we’re thinking of doing in the future, we have to all rethink. This is an amazing milestone.”
The groundbreaking results from the BICEP2 team confirm a long-held theory about the universe’s earliest moments and show that what we can see with visible light is just a tiny fraction of the cosmos, which may extend far beyond the edges we know of today. And they confirm the sometimes uneasy relationship between Einstein’s general theory of relativity, which works on large scales, and quantum mechanics, which governs the infinitesimally small scales.
It’s a discovery that could well be worthy of a Nobel Prize, said researchers who were not involved in the project.
“This is a watershed moment,” said California Institute of Technology astrophysicist Jamie Bock, one of the lead scientists on the BICEP2 collaboration.
The researchers used telescopes in Antarctica to stare at the cosmic microwave background radiation — a faint glow of low-energy light left over from the Big Bang that permeates the entire universe — and analyzed the light for signs of polarization. Swirling patterns left in the polarized light would be a clear sign that gravitational waves had left their mark.
Many theorists have long thought that if the universe had suddenly expanded, gravitational waves would have left a rippling mark on the structure of the universe. The discovery of these gravitational waves confirms that theory, but scientists still don’t agree on exactly what triggered inflation in the first place. And whatever inflation was, they do think that it was a mysterious, repulsive force — rather like the dark energy that pervades the universe today and is causing it to expand — but far, far more powerful.
Photo via Wikimedia Commons