Scientists have picked up the ripples in space-time caused by the death spiral of two celestial juggernauts – a neutron star and a black hole – for the first time.
The reverberations from these two objects were picked up using a global network of gravitational wave detectors, the most sensitive scientific instruments ever built.
University of Glasgow and University of Strathclyde are both part of the international network of scientists, the LIGO Scientific Collaboration (LSC), who made the observation through gravitational waves.
Gravitational waves are produced when celestial objects collide and the ensuing energy creates ripples in the fabric of space-time which carry all the way to detectors on Earth.
On 5 January this year, the Advanced LIGO detector in Louisiana in the US and the Advanced Virgo detector in Italy, observed gravitational waves from this entirely new type of astronomical system.
They picked up the final throes of the death spiral between a neutron star and a black hole as they circled ever closer and merged together.
Just days later, a second signal was picked up by Virgo and both ALIGO detectors again coming from the final orbits and smashing together of another neutron star and black hole pair.
This is the first time scientists have seen gravitational waves from a neutron star and a black hole. Previous gravitational wave detections have spotted black holes colliding, and neutron stars merging – but not one of each.
The UK has contributed greatly to the field of gravitational wave astronomy, from helping to design and build the incredibly sensitive detectors to continuing to search the universe for these signals.
Professor Stuart Reid from the Department of Biomedical Engineering at Strathclyde and elected Co-chair of the Optics Working Group of the LSC, said:
These detections confirm that there are populations of binary systems consisting of a neutron star and a black hole.
Such astrophysical systems can help answer many big questions about the Universe, from star formation and stellar evolution, to the expansion fate of our Universe.”
The LSC is made up of around 1,400 scientists from 19 countries, and includes researchers from 11 UK universities including Strathclyde, Glasgow, Birmingham, Portsmouth and Cardiff. The UK’s contribution to the collaborations is funded by the Science and Technology Facilities Council (STFC).
Since the first ever direct detection of gravitational waves in 2015, astronomers have predicted that this type of system – a black hole and neutron star merger – could exist, but without any compelling observational evidence.
Now that gravitational wave scientists have finally witnessed the existence of this new type of system, their detection will bring important new clues about how black holes and neutron stars form.
In future, as the LIGO and Virgo detectors are made even more sensitive, the team hope to detect many more neutron star black hole collisions, including cases where the black hole tearing apart the neutron star is observed in both gravitational waves and light, helping scientists to find out more about what neutron stars are made of.
The news comes as STFC has allocated £9.4million to UK universities and institutes for gravitational wave research, with hopes to continue the ground-breaking science, including £5.4 million to the consortium involving Strathclyde.
Professor Grahame Blair, STFC Executive Director of Programmes, said: “This exciting news from the gravitational wave community shows that space still holds secrets to be uncovered in this dynamic field of research.
“From first witnessing these ripples in space-time a few short years ago, we are now seeing a rich harvest of new observations coming in.
“This is the first time scientists have ever witnessed an event of this kind, and it goes to show why continuing to fund this research is vital in enhancing our understanding of the Universe.”