Wednesday 18 September 2019

Scientists detect ripples of Big Bang in deep space

The 10m South Pole Telescope and the BICEP (Background Imaging of Cosmic Extragalactic Polarization) Telescope at Amundsen-Scott South Pole Station is highlighted against the night sky
The 10m South Pole Telescope and the BICEP (Background Imaging of Cosmic Extragalactic Polarization) Telescope at Amundsen-Scott South Pole Station is highlighted against the night sky

Steve Connor

SCIENTISTS have detected the enigmatic ripples in deep space that were triggered by the Big Bang – the rapid expansion of the universe – during the earliest moments of its creation some 13.7 billion years ago.

In a ground-breaking experiment, astrophysicists have captured the first indirect images of so-called gravitational waves using a telescope at the South Pole designed to measure the cosmic background radiation left over from the Big Bang.

The findings are powerful confirmation of the events that took place at the very beginning of time when the universe expanded rapidly during a period known as inflation, which was the moment when gravitational waves were formed.

Albert Einstein first predicted the existence of gravitational waves a century ago in his theory of general relativity but no one has been able to measure them directly, despite a number of elaborate experiments around the world designed to do just that.

In the 1970s, cosmologists theorised that gravitational waves must have been generated immediately after the Big Bang, as the universe expanded during its inflationary period from being a pea-sized object to an entity that extends beyond the reach of the most powerful telescopes.

Gravitational waves are important to the theory of how large-scale structures such as galaxies, stars and planets were able to form from the smoothly distributed matter of the universe, but they have proved far too elusive to detect directly or indirectly – until now.

John Kovac of the Harvard-Smithsonian Centre for Astrophysics in Massachusetts and his colleagues were able to "see" gravitational waves by detecting swirly patterns of polarised radiation within the faint glow of the microwave background radiation left over as an "echo" of the Big Bang.

"Detecting this signal is one of the most important goals in cosmology today. A lot of work by a lot of people has led up to this point," Dr Kovac said.

The images emerged from data gathered by the BICEPS2 telescope in Antarctica.

"The South Pole is the closest you can get to space and still be on the ground. It's one of the driest and clearest locations on Earth, perfect for observing the faint microwaves from the Big Bang," Dr Kovac said.

The BICEPS2 telescope, which scans deep space for the cosmic microwave background radiation, detected swirls of polarised light in a pattern called B-mode, which could only be explained by the effect of gravitational waves, the scientists said.

MICROWAVES

The scientists said they were surprised to see such a strong signal of B-mode polarised radiation, which was bigger than theoretical cosmologists had predicted. They analysed the data over a period of three years to try to eliminate possible errors or interference, they said.

"This has been like looking for a needle in a haystack, but instead we found a crowbar," said Clem Pryke of the University of Minnesota, the co-leader of the research project.

Leonid Grishchuk of Cardiff University, who died last year, predicted 40 years ago that gravitational waves would result in B-mode polarisation in the cosmic microwaves' background.(© Independent News Service)

Irish Independent

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