For the first time, scientists see a black hole swallowing a neutron star

A team of international scientists confirmed detecting collision between a black hole and neutron star by analyzing gravitational waves created in January 2020.

According to Albert Einstein, gravity is just a complex fabric of space-time. Gravitational waves are ripples in that space-time fabric. In extreme events like the collision of two extremely dense bodies, ripples are created in the fabric. The concept of gravitational waves was just in theory books until its first detection in 2015 by LIGO (Laser Interferometer Gravitational-Wave Observatory). However, now the team has determined that these waves detected last January were a result of a neutron star being swallowed whole by its black hole partner.

Both black hole and neutron stars are the corpses of massive stars, with a black hole being even more massive than a neutron star.  Those two heavenly bodies are so massive that they bend the space-time fabric. During a collision, the fabric distorts a lot and hence creating enormous disturbance or ripples in the fabric. These distortions were detected by LIGO in the United States and by the Virgo detector in Italy.

The first merger detected on 5th January 2020, involved a black hole about 9 times the mass of our sun and a neutron star about 1.9 times the mass of our sun. The second merger was detected just after 10 days of the first merger, involving a 6 solar-mass black hole and a 1.5 solar mass neutron star. “With this discovery of neutron star – black hole mergers outside our galaxy, we have found the missing type of binary. We can finally begin to understand how many of these systems exist, how often they merge, and why we have not yet seen examples in the Milky Way,” Astrid Lamberts, a CNRS researcher at “Observatoire de la Côte d’Azur”, in Nice, France said in a statement.

The location of the first merger in space remains uncertain, though the second event is estimated to be roughly 1 billion light-years far from earth. Researchers were alerted to both events soon after they captured gravitational waves and searched for a flash of light, but none were found. This isn’t surprising due to the very large distance to these mergers, which means that any light coming from them no matter of what wavelength would be very dim and hard to detect with even the most powerful telescopes currently available. 



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