Astronomers from the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) in the USA have reported an astonishing scientific discovery that confirms Einstein’s theory from 100 years ago.
Namely, the researchers have observed elusive gravitational waves – ripples in space time caused by a violent cosmic event taking place in the distant Universe – whose existence was predicted by Einstein in his general theory of relativity.
The LIGO in the USA comprises of two giant detectors that are four kilometres long and 4000 kilometres apart, housing the most sensitive equipment ever made.
In order to aid the hunt for gravitational waves, LIGO was upgraded with the installation of ultra-high-performance optical mirrors, many of which were coated by researchers from CSIRO.
Dr Cathy Foley, Science Director of CSIRO Manufacturing, said the upgrade of the LIGO detectors increased the sensitivity of the system tenfold.
“Through the use of interferometry, which is the merging of two sources of light, LIGO is designed to measure changes between the two arms of each detector. The two giant detectors, which are located on opposite sides of the US, are then compared to confirm the findings,” Dr Foley said.
“The interferometer system includes a series of mirrors which are coated with multiple, precisely-controlled layers of optical materials to give the required reflective properties, and lastly a top layer of gold, designed for thermal shielding.
She said the coatings – which were developed and applied at CSIRO – are among the most uniform and precise ever made.
“This precision ensures that LIGO’s laser remains clean and stable as it travels through the detectors,” she said.
“We really are world leaders in this area, and are thrilled to play a part in this discovery.”
Physicists have concluded that the detected 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.
Dr Simon Johnston, Head of Astrophysics at CSIRO, described the discovery as “immensely important” for physics and astronomy.
“Gravitational waves exert a powerful appeal. Back in 1915 Einstein proposed that space-time is a four-dimensional fabric that can be pushed or pulled as objects move through it,” Mr Johnston said.
“If you run your hand through a still pool of water waves will follow in its path, spreading throughout the pool. Now that we’ve caught these waves, we can use them to see the Universe in entirely different ways to what was previously possible.”
The Australian Partnership in Advanced LIGO was led by Australian National University.
Researchers from CSIRO, the University of Adelaide, The University of Melbourne, the University of Western Australia, Monash University and Charles Sturt University, also gave significant contribution to the discovery.