Biggest black-hole collision ever recorded found using LIGO gravitational wave data

Luckily for us, the dramatic collision of two black holes took place nine billion light-years away.

A team of scientists has discovered ripples in space-time, called gravitational waves, from what they think is the biggest black hole collision ever recorded.

Scientists made this observation after revisiting old data from one of the world's largest observatory studying gravitational waves — the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) in the US.

The old data collected by the LIGO team revealed a merger of two separate stars pairs that collapsed into one another to form two separate black holes on 29 July 2017. The result was the merging of these black holes to form a third — the biggest one ever recorded.  The resulting black hole is roughly 80 times as large as the Sun, they said.

Luckily for us, the dramatic event took place nine billion light-years away.

"This event also had black holes spinning the fastest of all mergers observed so far. It is also by far the most distant merger observed," Professor Scott, lead scientist of the study at ANU, told university press.

The collision of two black holes - a tremendously powerful event detected for the first time ever by the Laser Interferometer Gravitational-Wave Observatory, or LIGO - is seen in this still image from a computer simulation released in Washington February 11, 2016. Scientists have for the first time detected gravitational waves, ripples in space and time hypothesized by Albert Einstein a century ago, in a landmark discovery announced on Thursday that opens a new window for studying the cosmos. via Reuters

The collision of two black holes — a tremendously powerful event detected for the first time ever by the Laser Interferometer Gravitational-Wave Observatory, or LIGO — is seen in this still image from a computer simulation released in Washington February 11, 2016. Scientists had, for the first time, detected gravitational waves — ripples in space and time hypothesized by Albert Einstein a century ago, opening a new window into studying the cosmos. via Reuters

Along with the collision, the team also discovered three other 'black holes mergers'.

"These detections of black-hole collisions greatly improve our understanding of how many binary black hole systems there are in the Universe, as well as the range of their masses and how fast the black holes spin during a merger," Scott added.

The LIGO researchers also intend to make the detector more sensitive to cataclysmic events further away in the universe. After the first observations were picked up by the LIGO team, the instrument was recalibrated and the data from it cleaned up for the next observation run.

"This increased the sensitivity of the detector network allowing our searches to detect more sources," Scott said. "We have also incorporated improved models of the expected signals in our searches."

The three smaller collisions were detected in August 2017 at distances of three billion and six billion light-years from Earth, causing black holes that were 56 to 66 times larger than the Sun.

"These were from four different binary black hole systems smashing together and radiating strong gravitational waves out into space," Scott said.

An artistic representation of the eye of a black hole.

An artistic representation of the eye of a black hole.

The expert stressed that observing these collisions will help to better understand how many binary black hole systems exist in the universe, as well as the range of their masses and the speed with which they spin during a merger.

The LIGO team, with researchers from around the world, has detected gravitational waves from ten different black hole-mergers and one neutron star collision over the past three years.

Neutron stars are the densest kinds of stars in the known universe, with a diameter of up to about 20 kilometres.

"Our new project will help to provide critical information about what we get from the merger of two neutron stars," Dr Karl Wette, a postdoctoral fellow at ANU.

The results and discoveries are expected to be published soon in the Physical Review X. 

Professor Scott will also be presenting the new results at the Australian Institute of Physics Congress in Perth later this month.





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