2023-07-07 15:06:34
Astronomers around the world announced Thursday that they have found the first evidence of a long-duration gravitational wave that creates a “background hum” throughout the universe. The breakthrough – made by hundreds of scientists using radio telescopes in North America, Europe, China, India and Australia – was greeted following Years of work—as a major milestone that opens a new window on the universe. First predicted by Albert Einstein over a century ago, gravitational waves are ripples in the fabric of the universe that travel through everything at the speed of light almost unhindered. Their existence wasn’t confirmed until 2015. , when American and Italian observatories detected the first gravitational waves resulting from the collision of two black holes. These “high-frequency” waves are the result of a single violent event that sends a powerful, short, rippling blast toward Earth. But for decades, scientists have been searching for low-frequency gravitational waves, which are believed to be They constantly roll through space like background noise. By joining forces under the banner of the International Consortium for the Timing Pulsar Matrix, scientists working on gravitational-wave detectors on several continents revealed Thursday that they have finally found strong evidence of such background waves. Michael Keith of the Timing Matrix said European pulsars told AFP “We now know that the universe is overwhelmed by gravitational waves.” An artist’s rendering of a network of pulsars affected by gravitational ripples generated by a supermassive black hole in a distant galaxy. (Aurore Simonnet/NANOGrav collaboration/Published via REUTERS) When gravitational waves travel through space, they very subtly compress and stretch everything they pass through. To find evidence of this compression and expansion at lower frequencies, astronomers examined pulsars, which are the dead cores For stars that have exploded into supernovae. Some spin hundreds of times per second, flashing beams of radio waves at very regular intervals, like cosmic beacons. This means they can act as a “very accurate clock,” Keith said. For the new research, radio telescopes were around the globe targeting a total of 115 pulsars across the entire Milky Way galaxy. Scientists then measured the incredibly small differences in the timing of the pulsations, looking for telltale signs of gravitational waves. French astrophysicist Antoine Petito said they were able to “detect the changes.” That was less than a millionth of a second over more than 20 years.” Maura McLaughlin of the American company Pulsar Search Collaboratory said she was “astonished” following seeing evidence of waves for the first time in 2020. “It was truly a magical moment,” she told a news conference. Scientists said the early evidence was consistent with Einstein’s theory of relativity and current science’s understanding of the universe. But they stressed that they had not yet definitively “discovered” the waves, because they had not reached the five level certainty of the gold standard. Five sigma indicates that there is a one-in-a-million chance that something is a statistical fluke. “We are frustratingly lacking in target,” Keith said, adding that there is a 99% chance that the evidence points to gravitational waves. Each country or group published Their research is separately published in a series of journals. Once all the data are combined, the five sigma mark might be reached within a year or two, said Steve Taylor, head of the NANOGrav Gravitational-Wave Observatory in North America. The main theory is that the waves come from pairs of supermassive black holes at the centers of slowly merging galaxies. Unlike the ones that cause gravitational waves detected previously, these black holes are almost incredibly massive — sometimes billions of times more massive than the Sun. Daniel said. Reardon, a member of Australia’s Parkes Pulsar Timing Array, told AFP that if confirmed, the waves would be “the sum of all binary systems of supermassive black holes orbiting each other in the cores of galaxies everywhere in the universe.” “The background buzz of all these holes,” Keith said. “It was like sitting in a noisy restaurant and hearing all these people talking.” Another theory is that gravitational waves might come from the rapid expansion that happened in the second following the Big Bang, a period called inflation that scientists keep from plain sight. Keith said Galaxies between Earth and the Big Bang would likely “drown” such waves. But scientists said low-frequency gravitational waves might tell us more regarding this early expansion into the future and perhaps shed light on the mystery of dark matter. It might also help them understand how wormholes form. black galaxies and their evolution better.
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