The LIGO Scientific Collaboration, involving researchers from MIT, Caltech and more than 80 other institutions worldwide, has won the Physics World 2016 Breakthrough of the Year, for its revolutionary, world-first direct observations of gravitational waves.
Gravitational waves are ripples in the fabric of space–time. The LIGO observations mark the end of a decades-long hunt for these interstellar undulations.
Almost 100 years after gravitational waves were first proposed by Albert Einstein in his general theory of relativity, the US-based LIGO collaboration detected two separate gravitational-wave events using the Advanced Laser Interferometer Gravitational-wave Observatory (aLIGO).
The first observation was made on 14 September 2015, and announced in February 2016. A second set of gravitational waves rolled through LIGO’s detectors on 26 December 2015, and this so-called “Boxing Day event” was officially announced in June this year.
Physics World editor Hamish Johnston said: “What’s been achieved by LIGO, particularly in a relatively short space of time, is truly incredible. The observations it has made are the first direct evidence of the existence of black holes, so LIGO has already changed our view of the universe.”
LIGO spokesperson Gabriela Gonzalez, of Louisiana State University, said: “We are very honoured to receive this recognition to not only a milestone discovery that has inspired the scientific community and the general public, but also to the teamwork that made it possible.”
Caltech’s David Reitze, executive director of the LIGO Laboratory, added: “It’s extremely gratifying for all of us working on LIGO that our efforts and accomplishments have been recognized. LIGO has opened a new window onto the cosmos. We are eager to learn what new secrets the universe reveals to us through gravitational waves!”
The measurements herald the start of the era of gravitational-wave astronomy and multi-messenger astronomy, whereby gravitational-wave observations will be combined with those made by optical and radio telescopes and other detectors observing the cosmos. To this end, LIGO’s twin detectors will soon be joined by a global network of gravitational wave detectors.
The gravitational waves from both events were produced via a cataclysmic event in the distant universe – the collision and eventual merger of two black holes. In the first event, two black holes of 36 and 29 solar masses, respectively, merged to form a spinning, 62-solar-mass black hole, some 1.3 billion light-years (410 mpc) away.
The gravitational waveform was picked up by the then newly-upgraded aLIGO detectors – one in Hanford, Washington, and the other in Livingston, Louisiana. When the signal reached the observatories, both detectors were still being calibrated. Despite this, the signal was so strong and clear that it can be “seen” in the data by eye.
Nine other achievements were shortlisted for the award, including the University of Glasgow’s construction of an inexpensive, compact, but highly sensitive gravimeter; the discovery of evidence that a rocky exoplanet orbits within the habitable zone of Proxima Centauri; the University of Strathclyde’s creation of a new microscope lens that combines of a large field of view with high resolution; and the creation of a single-atom engine.
You can read the full list of breakthroughs on physicsworld.com