Stories passed down about our history possess a power to unite us and inspire us, even when there's no proof the events actually happened. Sometimes myths become reality when we find evidence that the stories are actually true.
Recently, evidence of events that theoretically took place near the beginning of the universe, nearly 14 billion years ago, was discovered by a Harvard-led research team. If you aren't familiar with current theories in cosmology, however, you probably missed news that some are calling worthy of a Nobel Prize.
Patrick Brady, Professor of Physics and Director of the Leonard E. Parker Center for Gravitation, Cosmology and Astrophysics at the University of Wisconsin-Milwaukee, helped explain the story of our universe as we understand it today and why the new discovery seems to confirm our theories about it.
The Big Bang. “We normally think of an explosion happening in a single place,” said Brady. But this explosion “happened everywhere in space at the same time.” The universe was, admittedly, very small at this stage, so “everywhere in space” was essentially a single point. Nevertheless, “we see leftover remnants of the Big Bang coming at us from all different directions.” It's believed that some of those remnants can be seen in space today as microwaves, initially high-energy radiation released during the Big Bang that have stretched to lower frequencies as the universe has expanded.
Gravitational waves. When the Big Bang violently shook all the mass in the universe, we suspect it created some intense gravitational shock waves. Gravitational waves are able to tug on and twist (polarize) different forms of energy, including microwaves. Theoretically, said Brady, if there were gravitational waves early in the universe, they would have imprinted a distinctive polarization pattern on the energy released at that time.
Inflation phase. “That simple picture that we had of everything starting out at a point and then expanding at a very well-defined way isn't quite so simple: there are different phases,” explained Brady. For a fraction of a second immediately after the initial explosion, the “phase of inflation is when the rate at which the universe expands is extremely fast – much much faster than it is either before or after the time of inflation.” In fact, it's believed to have inflated faster than the speed of light.
Opaque phase. According to Brady, the universe for the first 300,000 to 400,000 years would have been an opaque cloud of scattered particles. Light would not have traveled freely through this cloud and would be essentially trapped. But as the opacity in the universe faded, the polarized energy would have theoretically begun streaming across the universe.
The first observations of cosmic microwave background radiation – polarized microwaves apparently everywhere in space and coming from all directions – were made 50 years ago.
March 17, 2014. Many other forces besides the Big Bang would have polarized the cosmic microwave background radiation over the last 14 billion years, explained Brady. Therefore, researchers measuring these microwaves have had to mathematically untangle the observed patterns to see what the original pattern would have looked like. The result, astonishingly, was nearly the exact pattern they would expect to see from gravitational waves passing through them. Suddenly, a bunch of theories felt much less theoretical.
With all good science, there comes a caveat. “It's a very complicated experiment with very complicated interpretation of the data,” said Brady, “so until we get a number of confirmations from other experiments, everyone views it as exciting. It looks right, but we really want to see it done again, independently, just to be sure.”
If the findings hold, it will confirm many theories about gravity also, which may help us figure out how to measure gravitational waves directly.