An ANU scientist has led the Australian team within a global scientific collaboration that has proven the existence of gravitational waves, 100 years after their existence was predicted by Albert Einstein’s General Theory of Relativity.
The confirmed observation of a gravitational wave, ripples in space caused by the collision of two black holes, is a major discovery and opens up new fields in physics and astrophysics. It will give scientists a new way to study the universe, black holes, dark matter and gravity.
More than 1,000 scientists around the world have been involved in the research, including the collaboration of Australian universities through the Australian Consortium for Interferometric Gravitational Astronomy, led by Professor David McClelland from The Australian National University.
“For the first time, we’ve been able to observe a gravitational wave, created 1.3 billion years ago by the collision of two massive black holes,” Professor McClelland said.
“This observation confirms that gravitational waves do exist. It is a moment that will be remembered for a thousand years.”
His ANU colleague Professor Susan Scott, who studies General Relativity, said observing this black hole merger was an important test for Einstein’s theory.
“It has passed with flying colours its first test in the strong gravity regime which is a major triumph.”
“We now have at our disposal a tool to probe much further back into the Universe than is possible with light, to its earliest epoch.”
Other Australian partners in ACIGA are the University of Adelaide, the University of Western Australia (UWA), The University of Melbourne, Monash University and Charles Sturt University. The research is published in Physical Review Letters.
The gravitational waves were detected by the twin detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) in the United States, in Louisiana and in Washington state.
The gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole. The collision is the most violent event ever recorded in the universe.
The ANU, UWA and University of Adelaide helped build crucial components of the LIGO detectors used to find the gravitational waves. Australian institutions were also heavily involved in analysing the data.
Already, spinoffs from the technology are being used and developed for commercial applications, such as the search for oil and gas and to measure groundwater from space.
The Australian government, through the Australian Research Council, has made significant contributions to the project.
The success of LIGO promised a new epoch of discovery, said Professor Andrew Melatos, from The University of Melbourne.
“Humanity is at the start of something profound. Gravitational waves let us peer right into the heart of some of the most extreme environments in the Universe, like black holes and neutron stars, to do fundamental physics experiments under conditions that can never be copied in a lab on Earth,” Professor Melatos said.
ANU designed, constructed, installed and commissioned a system that stabilises the experiments. The system also pulls the system back into line if it is disturbed, for example by a magnitude 7 earthquake anywhere in the world.
The university team also built, installed and commissioned 30 small optics steering mirrors for routing the signal beam around the interferometer and into the detectors.
ANU searched LIGO data for gravitational waves from young supernova remnants and worked with the University’s SkyMapper telescope to look for flashes of light associated with the first observation of gravitational waves.
CSIRO was contracted by LIGO to provide coatings for some mirrors, precisely controlled layers of optical materials and a top layer of gold, designed for thermal shielding. They are among the most uniform and highly precise ever made.
Photo: Black hole merger simulation (SSX via ANU Media)