Gravitational wave discoveries could be weekly by 2018

28 Sep 2017

Image: Helen Dream/Shutterstock

The fourth detection of gravitational waves in the distant universe has provided us with an even greater scientific understanding of spacetime.

The confirmation of the discovery of gravitational waves in 2015 was a watershed moment in astronomy, supporting a century-old Albert Einstein theory that promised a new era of scientific comprehension.

The research group behind the original detection, the Laser Interferometer Gravitational-Wave Observatory (LIGO), confirmed the detection of a fourth wave on 14 August.

For LIGO, it was a major breakthrough in its ability to detect future gravitational waves as it marked the first time that three of its laser interferometers picked up the wave, including its newest observatory, Advanced Virgo, in Pisa, Italy.

With a greater number of detectors, LIGO said, there is a better chance to pick up more and more layers of detail on the phenomenon.

Based on its findings, the ripples in spacetime were emitted during the final moments of the merger of two black holes, with masses about 31 and 25 times the mass of the sun, respectively, and located about 1.8bn light years away.

To add more mind-boggling numbers to the mix, the newly produced spinning black hole has about 53 times the mass of our sun, which means that about three solar masses were converted into gravitational wave energy during the main event.

Honing in like a laser beam

The hope now is that by its next observing run, planned for autumn 2018, LIGO could be detecting gravitational waves as often as weekly, if not multiple times per week.

“It is wonderful to see a first gravitational wave signal in our brand new Advanced Virgo detector only two weeks after it officially started taking data,” said Jo van den Brand, spokesperson for the Virgo collaboration.

“That’s a great reward after all the work done in the Advanced Virgo project to upgrade the instrument over the past six years.”

The Italian detector is envisioned as ‘LIGO 2.0’, however, even though it is less sensitive than the original LIGO detectors, algorithms within the original observatories confirmed Advanced Virgo’s measurements.

The organisation added that the volume of universe likely to contain gravitational waves shrinks by more than a factor of 20 when moving from a two-detector network to a three-detector network.

This will allow greater precision in measuring, with the hope that the entire astronomical community could make a number of discoveries, including multi-messenger observations.

Fred Raab, LIGO associate director for observatory operations, said: “As we increase the number of observatories in the international gravitational wave network, we not only improve the source location, but we also recover improved polarisation information that provides better information on the orientation of the orbiting objects as well as enabling new tests of Einstein’s theory.”

Colm Gorey was a senior journalist with Silicon Republic