Have gravitational waves, an Einsteinian prediction based on general relativity, been detected? The physics rumor mill is propagating speculation about a weighty discovery, but what’s the big deal? (See update below)
The Harvard-Smithsonian Center for Astrophysics will be hosting a press conference Monday, March 17, 2014, to announce a “major discovery.” What is the announcement? It could be anything.
First, let’s point out that we’ve seen public leaps to conclusions end badly before, as recently as 2012, when a principal investigator for the Mars Science Laboratory’s SAM instrument said “This data is gonna be one for the history books.” It turns out we may have overreacted (Universe Today). The speculation about tomorrow’s announcement appears to come from within the physics community, not the general public, but we should avoid getting ahead of ourselves.
Rumours have been rife in the physics community about an announcement due on Monday from the Harvard-Smithsonian Center for Astrophysics. If there is evidence for gravitational waves, it would be a landmark discovery that would change the face of cosmology and particle physics.
Gravitational waves are the last untested prediction of Albert Einstein’s General Theory of Relativity. They are minuscule ripples in the fabric of the universe that carry energy across space, somewhat similar to waves crossing an ocean. Convincing evidence of their discovery would almost certainly lead to a Nobel prize.
Shannon Hall of Universe today expanded on the ideas surrounding the speculation, explaining why its implications would be important.
Not only will detecting this slight polarization pattern in the CMB allow astronomers to uncover evidence of primordial gravitational waves but they will provide proof that immediately after the big bang the universe expanded exponentially — inflated — by at least a factor of 1025. While the theory of inflation is a pillar of big bang cosmology and helps explain key features of the observable universe today (i.e. why the universe is outstandingly uniform on such massive scales), many physicists don’t buy it. It remains a theoretical framework because we can’t explain what physical mechanism would have driven such a massive expansion, let alone stop it.
Inflation is the only mechanism with the ability to amplify gravitational waves, born from quantum fluctuations in gravity itself, into a detectable signal.
So to reiterate, why would this be important? Bill Nye summed it up a few years ago during The Amaz!ng Meeting:
Again, these rumors are professional speculation, so we’ll have to wait until tomorrow’s announcement, scheduled for 1200 EDT, to find out. Repeat: the discovery could be anything. It’s natural to get excited, but let’s not let speculation drive us to disappointment if they announce something that, while awesome, isn’t what was expected.
The press conference announced the researcher’s conclusions.
In a discovery physicists are calling “huge,” “extraordinary” and “spectacular,” a team of observers using a microwave-sensitive telescope at the South Pole has found the first direct evidence of gravitational waves—and the strongest proof of inflation to date, all in one shot.
The new results do have to be verified. Even though the BICEP2 team methodically checked and rechecked its work to rule out any mistakes, nobody, including Kovac and his colleagues, can be 100 percent certain until independent groups, using their own instruments, see the polarization signal too. That shouldn’t take long, given that cosmologists at Princeton, Berkeley, the University of Minnesota, the Goddard Spaceflight Center, the University of Chicago and more were already in the hunt. “Whether it’s correct or incorrect“ says Kamionkowski, who strongly favors the former, “will be known very quickly.”
Press announcements are all well and good, but the real meat in this story lies in the BICEP2 team’s research, which can be accessed via a prepublication copy submitted for review. Their results are available here and here.
The real story is opening ahead of us, as these results continue to be verified, replicated, and applied to existing questions, creating new ones about our universe’s expansion.
- Cosmic News: Astronomers Find the Twisted Fingerprints of Inflation in the Background Glow of the Universe (Bad Astronomy)
- Gravitational Waves in the Cosmic Microwave Background (Preposterous Universe)
- Have physicists finally detected gravitational waves? (io9.com)
- Proof of Inflationary Universe To Be Announced? (Sky & Telescope)