CAMBRIDGE, Mass. – When scientists jubilantly announced last week that a telescope at the South Pole had detected ripples in space from the very beginning of time, the reverberations went far beyond the potential validation of astronomers’ most cherished model of the Big Bang.
It was the second time in less than two years that ideas thought to be radical just decades ago had been confirmed (at least so the optimists think) by experiment.
The first was the discovery of the Higgs boson, associated with an energy field that gives mass to other particles, announced in July 2012.
Now the South Pole telescope team, led by John M. Kovac of the Harvard-Smithsonian Center for Astrophysics, has presented physicists with another clue.
The ripples detected by the telescope, BICEP2, were faint spiral patterns from the polarization of microwave radiation left over from the Big Bang.
These gravitational waves are the long-sought markers for a theory called inflation, the force that put the bang in the Big Bang: an antigravitational swelling that began a trillionth of a trillionth of a trillionth of a second after the cosmic clock started ticking. Scientists have long incorporated inflation into their standard model of the cosmos but, as with the existence of the Higgs boson, proving it had long been just a pipe dream.
Astronomers say they expect to be studying the gravitational waves from mountaintops, balloons and perhaps satellites for the next 20 years, hoping to gain insight into mysteries like dark matter and dark energy.
The cosmic Kahuna that now dangles before astronomers and physicists is understanding what caused inflation. What is this stuff that “turns gravity on its head” – as Alan Guth of the Massachusetts Institute of Technology, a founder of inflation theory, has put it – and blew up the universe?
Antigravity may sound like a crazy science-fiction idea, but Albert Einstein himself introduced the notion into physics. Known as the cosmological constant, he inserted into his equations to account for the fact that the universe didn’t collapse.
He later abandoned the cosmological constant, calling it a mistake, but it was resurrected 15 years ago when astronomers discovered that the expansion of the universe was speeding up because of the mysterious force called dark energy. As with inflation, the repulsion is part of space itself: The bigger the universe gets, the more powerfully it pushes apart, resulting in an exponential runaway expansion.
The recently discovered Higgs field could also behave in this way. It was by playing mathematically with a version of the Higgs field in 1979 that Guth stumbled on the concept of inflation.
In the years since, dozens of versions of inflation have been proposed.
Knowing inflation’s identity could be crucial if scientists are ever to unwind cosmic history back to the beginning, when they suspect the universe was ruled by a single unified force, not the four distinct forces we know today: gravity, electromagnetism and strong and weak nuclear forces.