Did Scientists Finally Detect Gravitational Waves?
Yesterday morning, Lawrence Krauss, a cosmologist at ASU, tweeted that he had received confirmation of a long-standing rumor that gravitational waves have been discovered, sending the scientific community into a tailspin.
My earlier rumor about LIGO has been confirmed by independent sources. Stay tuned! Gravitational waves may have been discovered!! Exciting.— Lawrence M. Krauss (@LKrauss1) January 11, 2016
Why is this so huge?
The detection of gravitational waves is the equivalent of astronomers discovering a new sense. With telescopes, we can see the universe. But by tapping into gravitational waves, they can 'listen" to it as well. Scientists would be able to "hear" stars colliding with one another, the destruction of matter in black holes, and the combustion of distant stars.
These gravitational waves are actually ephemeral ripples in the fabric of the universe - the last untested prediction of Einstein's general theory of relativity and possibly corroborating evidence of the Big Bang and cosmic inflation. In simpler terms, these waves are thought to be created by the acceleration of a mass, which radiates energy in the form of gravity. As these waves ripple across the universe, they cause atoms to bob like boats on a choppy ocean. The problem comes with the size of this displacement, which is much smaller than even the width of a single atom, making it incredibly difficult to detect.
Physicists and engineers have spent decades developing detectors known as interferometers. Each machine consists of two several-mile-long arms that stretch out at right angles. Mirrors bounce laser lights along these arms repeatedly, supposedly in sync. If there are any passing gravitational waves, they would fractionally alter the laser paths, causing them to fall out of sync - at least in theory. The scientists manning of the interferometers, dubbed Ligo, are in the process of writing up a paper that describes a gravitational wave signal.
The next big question is: are the rumors true?
Krauss said he was about 60% confident that the rumor was true, but wasn't going to jump to any conclusions until he saw the data. His dubiousness is probably for the best, especially after the 2014 mishap with BICEP2. Harvard researchers called a press conference to announce the discovery of gravitational waves in light of data from BICEP2, only to discover that the signal they received was most likely produced by space dust.
And there are just as many confounding variables with the rumored data from Caltech's Laser Interferometer Gravitational-Wave Observatory (LIGO). A gravitational wave researcher explains that "there are many noise sources... that could at first glance look promising. Hence, it would be a bold call to come to any conclusions before the analysis has been completed." Scientists also perform engineered runs with injected signals that mimic discoveries. Though Krauss later tweeted that he had received information that this discovery was not just a blind signal, word-of-mouth can't always be trusted.
Plus, physicists involved with the LIGO project had predicted their first detection happening around January 2017, meaning that if this is true, they have managed to improve on that by a year. Still, nothing is for certain until LIGO's results are officially shared, something that Professor Gabriela Gonzalez, spokesperson for the LIGO collaboration, thinks is still a ways away.