Scientists Successfully Hear Gravitational Waves, NANOGrav Director: This Is The First Time

Illustration. (Wikimedia Commons/NASA, ESA and the Hubble SM4 ERO Team)

JAKARTA - International scientists for the first time have found evidence of a long-theoretic gravitational waveform that creates a "background buzz" thundering throughout the universe, observing the vague ripples caused by black hole motion that gently stretches and suppresses everything in the universe.

Last Wednesday, they reported successfully hearing the so-called low-frequency gravitational waves, changes in the structure of the universe due to movement and collisions of massive objects in space.

"This is really the first time we have evidence of a large-scale movement of everything in the universe," said Maura McLaughlin, one of the directors of NANOGrav, an international research collaboration that published the results in the 'The Astrophysical Journal Letters', as reported by the Daily Sabah of AP 29 June.

Einstein once said, as very heavy objects move across space, they create ripples that propagate through these structures. Scientists sometimes liken these ripples to the background music of the universe.

In 2015, scientists used an experiment called LIGO to detect gravitational waves for the first time, suggesting Einstein was right.

"But so far, the method has only been able to capture waves at high frequencies," explained NANOGrav member Chiara Mingarelli, astrophysicist at Yale University.

The fast "witting" comes from certain moments when black holes are relatively small and stars die colliding with each other, said Mingarelli.

In a recent study, scientists are searching for waves at a much lower frequency. This slow ripple could take years or even decades to rotate ups and downs, and may come from some of the largest objects in our universe.

The background noise they found was "harder" than some scientists thought, Mingarelli said.

This could mean there are more, or larger, black hole mergers that occur in space than suspected, or point to other sources of gravitational waves that could challenge our understanding of the universe.

Separately, Szabolcs Marka, an astrophysicist at Columbia University who was not involved in the study, said galaxies across the universe continued to collide and join together. Today, scientists believe very large black holes in the center of this galaxy also assembled and were locked in a dance before finally collapsing with each other.

Black holes transmit gravitational waves as they spin in these pairs, known as binaries.

"The biner of supermassive black holes, slowly and calmly orbiting each other, is the tenor and bass of cosmic operas," explains Marka.

No instrument on Earth can capture the ripples of this giant. So "we have to make a detector roughly the size of a galaxy," said NANOGrav researcher Michael Lam of the SETI Institute.

Results released this week include 15-year data from NANOGrav, which has used telescopes across North America to search for the wave. Other gravitational wave hunting teams around the world have also published research, including in Europe, India, China, and Australia.

Scientists directed the telescope to a dead star called a pulsar, which sent a flash of radio waves while rotating in the sky like a beacon.

This burst is so regular that scientists know exactly when radio waves should arrive on our planet - "like a very regular clock beating deep into space," said NANOGrav member Sarah Vigeland, astrophysicist at the University of Wisconsin-Milwaukee.

But, as gravitational waves bend the spacetime line, they completely change the distance between the Earth and this pulsar, throwing away that stable beat.

By analyzing minor changes in the rate of beats across a variety of pulsars, scientists can find out that gravitational waves are passing through it.

The NANOGrav team monitors 68 pulsars in the sky using the Green Bank Telescope in West Virginia, the Arecibo telescope in Puerto Rico, and the Very Large Array in New Mexico. Other teams found similar evidence from dozens of other pulsars, which were monitored with telescopes around the world.

However, Marc Kamionkowski, an astrophysical expert at Johns Hopkins University who was not involved in the study, said the method was unable to track where exactly this low-frequency wave came from.

The researchers hope, by continuing to study this type of gravitational wave, it can help learn more about the largest objects in the universe, opening new doors to "cosmicararcheology" that can trace the history of black holes and the merging of galaxies around us, Marka said.