Scientists Confirm Black Hole And Neutron Star Collisions in World-First Discovery (video)

Scientists have unambiguously confirmed the collision of a black hole and a neutron star for the first time: the fateful moment when two extreme objects collide in an event so massive that its ripples across the cosmos can still be discerned a billion years later.

Surprisingly, an international collaboration of thousands of scientists has now reported that this astronomical discovery has been made not once, but twice.

Researchers detail the detection of gravitational waves resulting from two separate and distinct neutron star-black hole mergers – each registered by astronomers just 10 days apart in January 

2020 – in a new study confirming this world-first observation.

Scientists have observed dozens of mergers of pairs of black holes and several mergers of pairs 

of neutron stars. But a collision between a black hole and a neutron star, although predicted by scientists, was not detected.

“It’s an awesome milestone for the nascent field of gravitational-wave astronomy,” says astrophysicist Rory Smith from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) at Monash University.

“Neutron stars merging with black holes are amongst the most extreme phenomena in the Universe. Observing these collisions opens up new avenues to learn about fundamental physics, as well as how stars are born, live, and die.”

Artist’s impression of gravitational waves generated by a neutron star-black hole binary. (Mark Myers/OzGrav/Swinburne University)

The virtually simultaneous discovery of the two events – called GW200105 and GW200115 – speaks to the speed with which the field of gravitational wave science is evolving.

Researchers have now detected gravitational waves from dozens of events – in total, about 50 individual instances of black holes colliding with other black holes or neutron stars colliding with other neutron stars – in less than half a decade since the first confirmed discovery of gravitational waves.

Researchers have now detected gravitational waves from dozens of events – in total, about 50 individual instances of black holes colliding with other black holes or neutron stars colliding with other neutron stars – in less than half a decade since the first confirmed discovery of gravitational waves.

A’mixed’ collision representing the merger of a neutron star and a black hole – known as an NSBH binary – had never been confirmed before, despite scientists picking up signals that were potentially suggestive of such a neutron star-black hole collision in the past.

Now, however, the discovery is unambiguous.

The first event, GW200105, was detected on 5 January 2020, involving a black hole (with about nine times the mass of the Sun, or 8.9 solar masses) colliding with a 1.9-solar-mass neutron star.

This collision took place about 900 million years ago, even though we’ve only just detected the gravitational waves rippling out from the two objects merging.

GW200115, discovered on January 15, 2020, is even older, having formed from the merger of a 6-solar-mass black hole and a 1.5-solar-mass neutron star around 1 billion years ago.

“These collisions have shaken the Universe to its core and we’ve detected the ripples they have sent hurtling through the cosmos,” says astrophysicist Susan Scott from Australian National University (ANU).

“Each collision isn’t just the coming together of two massive and dense objects. It’s really like Pac-Man, with a black hole swallowing its companion neutron star whole.”

These binary systems have been predicted to exist for decades, but have never been observed before. Now, thanks to the detection of gravitational waves from their collisions, we know that these pairs do exist, even though many questions still remain.

“We’ve now seen the first examples of black holes merging with neutron stars, so we know that they’re out there,” says gravitational-wave astronomer Maya Fishbach from Northwestern University.

“But there’s still so much we don’t know about neutron stars and black holes – how small or big they can get, how fast they can spin, how they pair off into merger partners. With future gravitational wave data, we will have the statistics to answer these questions, and ultimately learn how the most extreme objects in our Universe are made.”

The findings are reported in The Astrophysical Journal Letters.

READ MORE: See the Most Detailed Picture of the Sun’s Surface Ever Taken


 

Leave a Reply

Your email address will not be published. Required fields are marked *