Why a rumor about the discovery of something Einstein predicted 100 years ago is going viral
(Uploaded by Cfoellmi~commonswiki on Wikipedia)
One of the two tunnels that make up LIGO based in Hanford, Washington.
On Monday, theoretical physicist Laurence Krauss sent the scientific community on Twitter reeling when he suggested that researchers may have detected, for the first time, an astrophysical phenomenon called gravitational waves.
Right now, the rumor is just that. The scientists to which the rumor refers work at the Laser Interferometer Gravitational-Wave Observatory (LIGO) and told Business Insider that there is no basis for such a claim, yet.
"We are still taking data, and we won't finish analyzing and reviewing results until at least a month or two later," Gabriela Gonzalez, LIGO spokesperson and Louisiana State University physics and astronomy professor, told Business Insider.
She added: "The instruments are working great, but ... I don't have any news with analysis results to share, yet."
But what if the rumor turns out to be real? Well, the prospect of what that would mean for science is what earned Krauss's Tweet 4,250% more retweets than his usual 40 or so — overnight.
What are gravitational waves and why do they matter?
(LLacertae on Flickr)
Artist's concept of gravitational waves in space.
Albert Einstein first predicted the existence of gravitational waves in 1916.
According to his theory of general relativity, a number of incredibly powerful cosmic systems across the universe will generate measurable ripples in the fabric of space-time called gravitational waves.
One example is two black holes orbiting one another that are eventually destined to collide.
When a smaller black hole meets a larger one, the two attract one another through tremendous gravitational forces. As the smaller black hole inches toward its inevitable doom, it accelerates through space at an ever-increasing rate toward the larger black hole, and, in so doing, generates gravitational waves.
Over 30 years ago, a pair of scientists using the radio telescope in Puerto Rico made the first indirect detection of gravitational waves by observing the behavior of a distant pulsar binary — a pair of rapidly rotating neutron stars (the densest objects in the universe next to black holes). This indirect detection gave fuel for larger projects, like LIGO and the BICEP2 telescope.
In 2014, the BICEP2 team reported the discovery of gravitational waves, but the discovery was later disproved.
To this day, scientists have yet to confirm the existence of gravitational waves with direct, observational evidence, which is why projects like LIGO are so important.
"The detection of gravitational waves would be a game changer for astronomers in the field," Clifford Will, a distinguished profess of physics at the University of Florida who studied under famed astrophysicist Kip Thorne told Business Insider in 2015. "We would be able to test aspects of general relativity that have not been tested."
Not only that, the ability to observe gravitational waves would open a whole new frontier of astronomy. The same way that astronomers today use light waves to study the universe, they could also use gravitational waves to see cosmic objects — such as colliding black holes — like never before.
How to snag a gravitational wave
(LIGO)
LIGO first began sniffing for gravitational waves in 2002. And between 2002 and 2010, the $620 million experiment came up empty handed.
To better the odds, engineers began upgrading LIGO to eventually make it 10 times more sensitive to gravitational waves.
Last September, scientists turned the new-and-improved machine on and began taking data with, what is now called Advanced LIGO.
The way Advanced LIGO works is that it consists of two identical machines that are located 1,865 miles apart — one is in Livingston, Louisiana and the other is in Hanford, Washington.
At each detector, there are two equally-long tunnels with a mirror at the end (one of the mirrors is shown in the image above). Scientists split a laser beam in two and then fire each half down one of the two tunnels. When the two beams reflect off the mirror, they should both return at the same time, since they're traveling at the speed of light.
However, if a gravitational wave passes through the detector the same time the laser is traveling through the two tunnels it will ever-so-slightly warp the space-time surrounding the tunnels. As a result, scientists expect to see a slight difference in time between when the first and second halves of the beam return.
Compared to the length of light waves we see with our eyes, which are micrometers in size (about the width of a human hair), gravitational waves are huge. This is why the distance between each LIGO detector is over 1800 miles, because that's about how long LIGO scientists think the gravitational waves they're searching for should be.
Therefore, if one detector observes a gravitational wave, it should mean the other detector should measure the same signal, offering immediate confirmation that the observation at the first detector isn't a fluke.
Scientists at LIGO aren't taking any chances with this experiment — they don't want another BICEP2 incident. Before they announce a discovery, the data will have been fully vetted twice-over by their expert peers.
But if they do succeed, it will revolutionize astronomy as we know it.
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