These bursts are so regular that scientists know exactly when the radio waves are supposed to arrive on our planet - “like a perfectly regular clock ticking away far out in space,” said NANOGrav member Sarah Vigeland, an astrophysicist at the University of Wisconsin-Milwaukee. The scientists pointed telescopes at dead stars called pulsars, which send out flashes of radio waves as they spin around in space like lighthouses. Other teams of gravitational wave hunters around the world also published studies, including in Europe, India, China and Australia. The results released this week included 15 years of data from NANOGrav, which has been using telescopes across North America to search for the waves. So “we had to build a detector that was roughly the size of the galaxy,” said NANOGrav researcher Michael Lam of the SETI Institute. No instruments on Earth could capture the ripples from these giants. “Supermassive black hole binaries, slowly and calmly orbiting each other, are the tenors and bass of the cosmic opera,” Marka said. The black holes send off gravitational waves as they circle around in these pairings, known as binaries. As this happens, scientists believe the enormous black holes at the centers of these galaxies also come together and get locked into a dance before they finally collapse into each other, explained Szabolcs Marka, an astrophysicist at Columbia University who was not involved with the research. Galaxies across the universe are constantly colliding and merging together. These slow ripples can take years or even decades to cycle up and down, and probably come from some of the biggest objects in our universe: supermassive black holes billions of times the mass of our sun. In the latest research, scientists were searching for waves at much lower frequencies. Those quick “chirps” come from specific moments when relatively small black holes and dead stars crash into each other, Mingarelli said. But so far, those methods have only been able to catch waves at high frequencies, explained NANOGrav member Chiara Mingarelli, an astrophysicist at Yale University. In 2015, scientists used an experiment called LIGO to detect gravitational waves for the first time and showed Einstein was right. Scientists sometimes liken these ripples to the background music of the universe. “It’s really the first time that we have evidence of just this large-scale motion of everything in the universe,” said Maura McLaughlin, co-director of NANOGrav, the research collaboration that published the results in The Astrophysical Journal Letters.Įinstein predicted that when really heavy objects move through spacetime - the fabric of our universe - they create ripples that spread through that fabric. They reported Wednesday that they were able to “hear” what are called low-frequency gravitational waves - changes in the fabric of the universe that are created by huge objects moving around and colliding in space. NEW YORK – Scientists have observed for the first time the faint ripples caused by the motion of black holes that are gently stretching and squeezing everything in the universe.
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