Gravity speaks

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The discovery of gravitational waves could allow some of the universe’s greatest secrets to be answered

In the early hours of 14 September 2015, something truly momentous occurred; an event of seismic significance for all of humanity, and in which the University of Adelaide played a pivotal role.

When each arm of the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors—one located in Livingston, Louisiana, and the other in Hanford, Washington—moved just a billionth of a billionth of a metre, gravitational waves were proven to exist; and a fundamentally new ‘sense’ with which to observe the cosmos was harnassed.

The LIGO research is conducted by a vast global network of over 1,000 scientists from more than 90 universities, collectively known as the LIGO Scientific Collaboration (LSC), with the University of Adelaide contributing critical technological input.

The University’s research team—currently led by Associate Professor Peter Veitch, Head of Physics, and including Professor Emeritus Jesper Munch, Associate Professor David Ottaway and Dr Won Kim—helped develop and install ultra-high-precision optical sensors to correct distortion of the LIGO detectors’ laser beams. It was this correction that enabled the unprecedented sensitivity needed to detect such minute signals.

“One of our PhD students, Ms Elli King, was actually working at the LIGO Hanford Observatory when the wave was discovered,” says Associate Professor Veitch. “She was part of the team that conducted the exhaustive checks to ensure the signal was genuine.”

The breakthrough confirms Albert Einstein’s prediction of such waves 100 years ago in his general theory of relativity, and is widely considered the most important scientific discovery of our lifetimes. According to Associate Professor Veitch, it could well help scientists answer some of the universe’s most intriguing questions.

“Observing these ripples in space-time could help us work out, for example, how fast the universe is expanding and allow us to explore the dark and violent side of of the universe, including the explosion of massive stars in supernovae. We’re on the threshold of a potential revolution in which gravitational astronomy could dramatically change our understanding of the universe and its evolution.”

The Adelaide team operates as part of a national LSC member group known as the Australian Consortium for Interferometric Gravitational Astronomy (ACIGA), which also includes scientists from Australian National University, University of Melbourne, University of Western Australia, Monash University and Charles Sturt University.

The detection of the gravitational waves, produced by the cataclysmic merger of two black holes over one billion years ago, represents the culmination of decades of research and development in Australia and internationally.

“I’ve spent almost 40 years working towards this,” says Associate Professor Veitch. “Success is sweet.”

Related links:
Professor Peter Veitch – profile
Research Tuesdays – Gravity speaks presentation (8/3/16)
Faculty of Sciences
School of Physical Sciences
Media release – 12/2/16
LIGO Scientific Collaboration