OzGrav scientists win Australia’s most prestigious science awards: the 2020 Prime Minister’s Prizes for Science
Tonight four members of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) have been awarded the 2020 Prime Minister’s Prizes for Science for their critical contributions to the first direct detection of gravitational waves―a landmark achievement in human discovery: Chief Investigator Emeritus Professor David Blair (University of Western Australia); Deputy Director Professor David McClelland (Australian National University); Chief Investigator Professor Susan Scott (Australian National University); and Chief Investigator Professor Peter Veitch (University of Adelaide).
The Prime Minister’s Prizes for Science are Australia’s most prestigious awards for outstanding achievements in scientific research, research-based innovation and excellence in science teaching. This year’s recipients are four pioneering Australian physicists from OzGrav that contributed to the groundbreaking discovery of gravitational-wave signals from the collision of two black holes 1.3 billion years ago. This was made possible by decades of research and innovation of the team as part of the Laser Interferometer Gravitational-wave Observatory Scientific Collaboration (LSC).
Emeritus Prof. David Blair says: “It is wonderful to receive the Prime Minister's Prize for Science. It's a fitting tribute to all of the students and scientists who participated in this amazing quest that was finally rewarded with the detection of gravitational waves. This is a prize for physics in Australia.”
Emer. Prof. Blair created a large-scale high-optical power research facility in Gingin, Western Australia, to mimic Advanced LIGO interferometers and investigate the subtle interactions between light, sound and heat that would occur in full-scale detectors. His pioneering work predicted that laser light would scatter from sound in the mirrors, causing parametric instability at power levels far below that needed to obtain detector sensitivity. When this theory was validated during LIGO commissioning, Emeritus Professor Blair sent team members to help implement stabilisation methods that allowed the detectors to achieve sufficient power levels to make the first detection of gravitational waves.
In 1916, Albert Einstein first predicted the existence of gravitational waves―minute distortions in the fabric of space-time that are non-electromagnetic in nature and spread from their source at the speed of light; however, he believed they would never be detectable.
Prof. Peter Veitch says: “Einstein developed his theory of relativity in 1915, but people questioned whether gravitational waves really existed or whether they were just some sort of mathematical nonsense predicted by the theory. Since then there has been a large advance in our understanding of the Universe, and our research has focused on developing the technologies required to detect Einstein's theorised gravitational waves.”
Prof. Veitch’s University of Adelaide team invented and installed critical instrumentation for the Advanced LIGO detectors, namely their Hartman sensors. These sensors provide a solution to a major technological problem – the distortion of the laser beam within the detector – by measuring them simply and with a sensitivity that is 30-times better than any other sensor. The Hartman sensors are used at all stages of the detection process: commissioning, measurement and adaptive correction of the distortions, and optimising the detector sensitivity and stability.
“Over the last few decades, there were many scientists who either didn't believe that gravitational waves existed, or felt that they were simply too small to ever be detected,” explains Prof. Susan Scott. “We had enormous technological difficulties to overcome – everything had to be about a thousand times better, including the shapes of the mirrors, the frequency of the lasers, the acoustic wringing of the mirrors and the vibration isolation.”
Prof. Scott initiated the Australian effort in gravitational wave data analysis in 1998, and led Australian research in digging gravitational wave signals out of detector noise. Her Australian National University team contributed key components to the LIGO Data Analysis System through which the detection signal was processed in 2015, designing and conducting the first gravitational wave search to be carried out under Australian leadership.
In September 2015, recent advances in detector sensitivity led to the first direct detection of gravitational waves; two Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO) laser interferometers simultaneously detected a signal characteristic of a pair of black holes – 29 and 36 times the mass of the sun – merging into one. This was followed by a further detection in 2017, from the collision of two neutron stars. The first detection of its kind, this event solved a 50-year-old mystery confirming that these mergers are the source of previously observed high-energy gamma ray bursts, and of heavy metals such as gold, platinum and uranium in the Universe.
Prof. David McClelland says: “This achievement (gravitational wave detection) came about only through long term investment in basic R&D by the Australian Research Council, our universities and many similar organisations around the world. This investment has led to impactful science, impactful technologies and inspired a generation of scientists and engineers.”
Prof. McClelland led the Australian National University team that played a crucial role in designing, installing and commissioning Advanced LIGO’s lock acquisition system, and in the construction and installation of Australian hardware for precision routing of the laser beam. His pioneering quantum ‘squeezing’ technology (now installed in all detectors) is essential for boosting interferometer sensitivity to the current level where signals are detected weekly when in operation.
The impact of the first 2015 detection, the acclaimed ’discovery of the century’, has been immense, opening up previously unknown parts of the Universe, such as hidden black holes; understanding the origin of gamma ray bursts (and with the potential to discover how supernovae explode); and to even peer back to the beginning of time at the Big Bang.
The legacy of the team’s combined research ensures that Australia is now ‘front-and-centre’ in exploring this brand-new window into the Universe. “The pioneering work of our team over the last quarter of a century has ensured that Australia played a leading role in the first direct detection of gravitational waves,” says Prof. Susan Scott. “Australia is now in a position to be a powerhouse in the emergent field of gravitational wave astronomy.”
For OzGrav Director Professor Matthew Bailes (Swinburne University of Technology), the result is especially pleasing. “This is fantastic recognition of the role Australia has played in opening this new window on Einstein’s Universe. I’m thrilled for not only these four pioneers of the field in Australia, but for the future generations of scientists and engineers that will follow in their footsteps.”