Astronomers across the world announced on Thursday that they have found evidence of a long-theorised form of gravitational waves that create a 'background hum' travelling through the universe.

The breakthrough was made by hundreds of scientists using radio telescopes in North America, Europe, China, India, and Australia. The research has opened a new window into the universe.

It was first predicted by Albert Einstein more than a century ago stating that gravitational waves are ripples in the structure of the universe that travel through everything at the speed of light almost.

Their existence was not confirmed until 2015 when the US and Italian observatories detected the first gravitational waves created when two black holes were actually colliding.

These high-frequency waves were the result of a single violent event that sends a strong bust toward Earth.

For centuries, scientists have been searching for low-frequency gravitational waves which were thought to be constantly rolling in space like background noise.

Michael Keith of the European Pulsar Timing Array revealed, 'We now know that the universe is awash with gravitational waves.'

Gravitational waves as they pass through space, very well subtly squeeze and stretch everything they pass through. To find evidence, astronomers looked at the dead cores of stars that exploded in a supernova.

Some spin hundreds of times a second at extremely regular intervals like cosmic waves. This means they can act as a 'very very precise clock,' Keith said.

Radio telescopes around the world were aimed at a total of 115 pulsars throughout the Milky Way.

Searching for telltale signs of gravitational waves, scientists measure small differences in the timing of the pulses.

French astrophysicist Antoine Petiteau said they were able to 'detect changes of less than one-millionth of a second across more than 20 years'.

Some researchers were awestruck after first seeing evidence of the waves in 2020. It was really a magical moment for all.

The early evidence was consistent with Einstein's theory of relativity. But at that time it was emphasised that they had not detected the waves yet as they had not reached the gold-standard five sigma level of certainty which hints at a chance of one in a million in the statistical fluke.

There is now a huge probability that the evidence points to gravitational waves.

Each country or group in the consortium published their research in their journals respectively. Combining all the data, the five sigma mark could be reached in a year or two.

The leading theory is that the waves are coming from pairs of supermassive black holes sitting at the center of galaxies that are slowly merging. These black holes are unimaginably huge - sometimes billions of times bigger than the Sun.

Daniel Reardon, a member of Australia's Parkes Pulsar Timing confirmed that the waves would be 'the sum of all the supermassive black hole binary systems whirling around each other at the core of galaxies everywhere in the universe.

Keith said the 'background hum of all these black holes' was 'like sitting in a noisy restaurant and hearing all these people talking.'

Another theory is that the gravitational waves could be from the rapid expansion of the universe after the Big Bang.

These low-frequency gravitational waves could reveal more about this expansion and possibly throw light on the mystery of dark matter. It could also help them understand more about how black holes and galaxies form and evolve.

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Reference:

• ndtv.com