Two massive facilities that register gravitational waves in our universe are about to get switched back on in the United States. On April 1, facilities in Louisiana and Washington state that combine to make up the Laser Interferometer Gravitational-Wave Observatory (LIGO) will get back to doing research again after more than a year of being shut down so that their hardware could get upgraded.
More than a century ago Albert Einstein concluded that when massive objects like black holes collide they send shockwaves through space-time. These ripples or gravitational waves can be detected on Earth using precise scientific equipment.
Wave Detection Leads To Nobel Prize
Back in 2015 scientists detected gravitational waves from a black hole collision for the first time. This discovery was such a leap forward in physics that the three researchers responsible for the project won the Nobel Prize.
Since then many more collision events have been detected. So far 10 black holes smashing into each other have been recorded as well as a pair of neutron stars crashing together.
Once the facilities come back online after April 1 the research can continue now with even more improved equipment. "So far, we've seen 11 things. Maybe we'll see twice that many this year," says Joseph Giaime, head of the LIGO Observatory in Livingston, Louisiana.
The two facilities will join a third detector in Italy called VIRGO which significantly increases the group's chances of detecting the exact location of gravitational waves in the universe. Japan is also developing a facility called KAGRA that will come online sometime soon to join the group.
Astronomy Gets New Tool
Looking for gravitational waves is a new step for astronomy, which has previously spent most of its energy searching the skies for light. As black holes don't emit light, investigating them has always posed a problem.
These powerful detectors give researchers a whole new method for studying these mysterious objects. "Galileo invented the telescope or used the telescope for the first time to do astronomy 400 years ago. And today we're still building better telescopes," notes Gabriela González, professor of physics and astronomy at Louisiana State University. "I think this decade has been the beginning of gravitational wave astronomy. So this will keep making progress, with better detectors, with different detectors, with more detectors."
How It Works
The actual method of looking for gravitational ripples comes together from both high and low technologies. Each LIGO detector in the U.S is comprised of two long concrete pipes arranged in an “L” shape. Each arm of the shape extends roughly 3 kilometers.
Inside is a powerful laser that bounces back and forth inside the pipe. The laser is precisely measuring the length of the pipeline over and over again. When the gravitational wave passes through, distorting space, the length of the pipe changes. The laser can detect this change and scientist know that a cosmic event has occurred.
The change in length is a fraction of the width of a subatomic particle. LIGO will have a more public presence once it gets back online. If gravitational activity is detected an alert will go out so amateur agronomists can do their own scans of the night sky. When the neutron star collision was detected it created a visible natural firework display.
Researchers are excited about what the newly updated facilities might find. "That's how discovery happens," she says. "You turn on a new instrument, you point it out at the sky, and you see something that you had no idea existed."