In Summary

  • Third detection of gravitational waves
  • Waves formed when two black holes merged 
  • Final black hole was some 50 times the mass of our Sun



The Laser Interferometer Gravitational-wave Observatory (LIGO) has made a third detection of gravitational waves, ripples in space and time, demonstrating that a new window in astronomy has been firmly opened.

As was the case with the first two detections, the waves were generated when two black holes merged to form a larger black hole. In the latest merger, the final black hole was some 50 times the mass of our Sun. The recent detection, called GW170104, is the farthest yet, with the black holes located about three billion light-years away.

“The event released more energy in its last few orbits than that of rest of the entire universe, yet when the ripples passed the LIGO detector they made it vibrate by just one attometer, or 0.000000000000000001 metres”, says Professor Matthew Bailes, Director of the new Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav).

Despite this tiny displacement, the scientists from the LIGO and Virgo scientific collaborations were able to demonstrate the black holes exhibited a property known as “spin”.

"This is the first time that we have evidence that the black holes may not be aligned, giving us just a tiny hint that pairs of black holes may form in dense stellar clusters," says Bangalore Sathyaprakash of Penn State University, one of two lead editors for the publication.

“The LIGO detector lets us feel the gravitational wave, and we are on a mission to see the source of the event by looking through powerful telescopes.” says Postdoctoral Fellow Qi Chu from the University of Western Australia and member of the LIGO scientific collaboration and OzGrav.  

She is part of a team led by OzGrav Chief Investigator Professor Linqing Wen that is racing to create faster ways to crunch the LIGO data to minimise the time between the gravitational waves hitting earth and an alert being sent out for follow-up observations.

For OzGrav’s Deputy Director, Professor David McClelland, this latest discovery makes the impetus to continue work on upgrading the LIGO detector even more compelling. “Our quest to extend LIGO to detect other types of violent events, such as those from neutron stars, drives us to develop new technologies such as quantum squeezing optical devices to reach further into Einstein’s Universe.

The research is published in Physical Review Letters.

LIGO is funded by the National Science Foundation (NSF), and operated by MIT and Caltech, which conceived and built the project. Financial support for the Advanced LIGO project was led by NSF with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council) making significant commitments and contributions to the project. More than 1,000 scientists from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration. LIGO partners with the Virgo Collaboration, a consortium including 280 additional scientists throughout Europe supported by the Centre National de la Recherche Scientifique (CNRS), the Istituto Nazionale di Fisica Nucleare (INFN), and Nikhef, as well as Virgo’s host institution, the European Gravitational Observatory. Additional partners are listed at:

The ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) is funded by the Australian Government through the Australian Research Council Centres of Excellence funding scheme. OzGrav is a partnership between Swinburne University of Technology (host of OzGrav headquarters), the Australian National University, Monash University, University of Adelaide, University of Melbourne, and University of Western Australia, along with other collaborating organisations in Australia and overseas.

An OzGrav Educational Animation depicting the Binary Black Hole merger event GW170104, detected by LIGO on 4-Jan-2017 and confirmed on 1-Jun-2017. 

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