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Scientists discovered waves from a black hole that swallowed a neutron star



Nearly a billion years ago, a black hole seems to have eaten a dead star – "like Pac-Man," said Susan Scott, a physicist at the Australian National University.

Scott's team believes that the waves in the spacetime of this event, also known as gravitational waves, have just reached Earth. Such disturbances were first theorized by Albert Einstein, who in 1915 predicted that the acceleration of massive objects such as neutron stars or black holes would create "waves" in space and time. However, the first observations of gravitational waves did not occur until 2015, 100 years later.

Then, on August 1

4, gravitational wave detectors in the US and Italy picked up new gravitational waves that flew through the earth.

More research is needed to confirm the results, but there is a fair chance that the signals from the collision of a black hole are from a neutron star – the super-dense remnant of a star. That would be the third event scientists discovered using gravitational waves. In 2015, researchers discovered waves of two colliding black holes and in 2017 they observed the fusion of two neutron stars.

A collision between a black hole and a neutron star would complete the three crashes on the wish list, Scott said.

Space-time waves indicate violent events

When two black holes collide, they release enormous amounts of energy in the form of gravitational waves that can last for a fraction of a second and "be heard" throughout the universe. Have the right instruments ,
NASA Goddard

Einstein did not believe that gravitational waves would ever be detected – they seemed too weak to pick up on the earth amidst the sounds and vibrations. For 100 years he seemed right.

But scientists finally managed to capture these waves using the Laser Interferometer Gravitational Wave Observatory (LIGO) in Washington and its sister machine called Virgo in Italy.

In 2015, LIGO discovered the first gravitational waves caused by the collision of two black holes 1.3 billion light-years away. This discovery confirmed Einstein's general theory of relativity. Then, in 2017, LIGO and Virgo jointly identified the waves of two merging neutron stars.

The L-shaped LIGO Observatory in Hanford, Washington.
LIGO Laboratory / NSF

To confirm that this is actually a third discovery of gravitational waves, telescopes around the world are looking for x or ultraviolet light, National Geographic reported. If the neutron star had survived the collision long enough before the black hole had destroyed it, the dead star could have emitted light that would allow scientists to verify the findings.

However, black holes are so powerful that not even light escapes.

However, scientists studying gravitational waves have to be disappointed because LIGO and Virgo can trigger false alarms (cases where the detectors only pick up earth noise).

A worker inspects quartz fibers hanging a mirror inside the Virgo Gravitational Wave Observatory.
EGO / Virgo Collaboration / Perciballi

A possible neutron black hole collision was discovered, for example, in April Probably a false alarm. A signal of this volume has a one-to-seven chance of being a noise from the earth. Statistically, LIGO and Virgo could receive such a false signal every 20 months.

But there is a much lesser chance that LIGO and Virgo will detect a false signal that is as strong as the one they found this month. Researchers have calculated that this type of error should occur only once over a period longer than the age of the universe, National Geographic reported.

"This is something to enjoy much more," said Christopher Berry, physicist at Northwestern University and LIGO researcher, to National Geographic. "It's much more likely that a real one appears, which means it's worth investing more time and effort."

A very bright black hole?

A supercomputer simulation shows one of the most violent events in the universe: a pair of neutron stars that collide, merge and form a black hole. A neutron star is the compressed nucleus that remains when a star born with eight to thirty times the mass of the sun explodes as a supernova. Neutron stars pack about 1.5 times the mass of the sun to a sphere with a diameter of only 19 kilometers.
NASA Goddard

Scientists also analyze the data to confirm the exact size of the colliding objects.

Scott said that if these results turned out differently than expected, they could steer the team in a different direction: "There is the slight but intriguing possibility that the swallowed object was a very bright black hole – much easier than every other black hole we know in the universe, "she said.

If the smaller, swallowed object turned out to be a black hole, it would still be a groundbreaking discovery, since this type of black hole is considered physically impossible. It would open a whole new realm of tiny black holes for study.

"That would be a really great consolation prize," Scott said.


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