Two supermassive black holes will collide by the year 2125, and Earth will feel it

Two black holes are moving towards each other 500 million light-years from our solar system and will merge in about 100 years. When this happens, Earth will also feel the effects of the cosmic event. Study co-author Silke Britzen told BBC Science Focus, "We expect one (merged) black hole to remain.” The blazar at the core of the galaxy Markarian 501 caught the attention of scientists. This extremely luminous and ultrabright object is usually powered by a black hole. When they got a closer look, the researchers found that there was not one but two jet streams. This showed that the activity was happening because of two black holes that will collide in the next 100 years.

The blazar shoots jets of energy radiation into space as they consume objects at the centres of galaxies, which also reaches Earth. A central black hole acts as the source for them. But the blazar in the galaxy Markarian 501 appeared different from usual. Radio telescope data gathered over the years failed to reveal whether a supermassive black hole was at its core. The study was published in the journal Monthly Notices of the Royal Astronomical Society.

Two jets at the centre of the galaxy

To get a better look, they analysed over 83 datasets from the Very Long Baseline Array, which comprises 10 radio telescopes located in different parts of the world. The observations revealed that there was another jet looping counterclockwise around the blazar's centre. This led them to believe that each jet was originating from a different black hole, which are likely the mass of 100 million to one billion suns. Also Read: Did a comet explosion create atmosphere on this object beyond Neptune?

More evidence about the presence of two black holes emerged when they lined up nearly in 2022. The gravity of the first black hole bent the light emitted by the second jet, forming an Einstein ring. Gravitational lensing, a cosmic magnifying glass, confirmed that the blazar was coming from two supermassive black holes. Also Read: Sun may spare Earth and Mars, as study reverses course on death of our planet

The distance between the two black holes is about 250 to 540 times the distance between Earth and the sun. They are circling each other and complete one orbit in about 121 days. They are slowly coming closer, and a collision will be so powerful that the ripples through space-time will also reach Earth, where they would be picked up by gravitational wave detectors. It would be the most intense black holes ever recorded by humans.