An exceptional discovery which also bears the signature of researchers from the National Institute of Astrophysics (INAF) of Cagliari: astronomers have in fact announced that they have found evidence of a long-theorized form of gravitational waves which creates a " background hum " which it rumbles throughout the universe.
The breakthrough - achieved by hundreds of scientists using radio telescopes in North America, China, India, Australia, Europe and also in Sardinia, where the Sardinia Radio Telescope is operational - was hailed as a milestone that opens a new window on the universe .
The existence of these waves had been theorized by Albert Einstein but had never been proven so far.
Gravitational waves are ripples in the "fabric" of the universe that travel at the speed of light almost completely unhindered. Their existence wasn't confirmed until 2015, when US and Italian observers detected the first gravitational waves created by the collision of two black holes. These "high-frequency" waves were the result of a single violent event that sends a sharp, short, rippling blast toward Earth. But for decades, scientists have been searching for low-frequency gravitational waves, which are thought to be constantly moving through space as background noise. Joining forces under the banner of the International Pulsar Timing Array consortium, scientists working on gravitational-wave detectors on several continents have now revealed that they have finally found strong evidence for these background waves.
"We now know that the universe is flooded with gravitational waves," said Michael Keith, of the European Pulsar Timing Array .
To find evidence of this low-frequency pattern, astronomers looked at pulsars, the dead cores of stars that exploded in supernovae. Some rotate hundreds of times per second, flashing beams of radio waves at extremely regular intervals, like cosmic beacons. That means they can act like "a very, very accurate watch," Keith said.
