Black holes, thought to be too massive to collide, defy expectations

One of the black holes involved within this merger was thought to be too large to be involved in such an event, and produced a black hole which weighs about 85 times the sun.

A simulated image of a black hole. (photo credit: Wikimedia Commons)
A simulated image of a black hole.
(photo credit: Wikimedia Commons)
Scientists have detected a black hole collision previously thought to be impossible, which took place when the universe was half its current age, the scientific journal Nature reported.
At least one of the black holes involved within this merger was thought to be too large to be involved in such an event, as it weighs about 85 times the weight of the sun. The merger in turn produced a black hole of nearly 150 solar masses – the unit used to measure the mass of other stars, equal to 2×10^30 kg – which has never been observed before. The event was detected on May 21, 2019 and the two papers discussing it were published on Wednesday.
The main scenario the scientists who made the discovery assume to be the most likely scenario is that the two black holes involved in this merger were already a result of previous mergers, though this presents a problem, as a first merger usually causes a black hole to be ejected from a cluster of black holes, making another merger a rare occasion. It would be more likely if the merger took place in the center of a galaxy, where gravity would be strong enough to keep things relevantly close to each other.
“Everything about this discovery is mind-boggling,” said Simon Portegies Zwart, a computational astrophysicist at Leiden University in the Netherlands. He claimed that this confirms the existence of "intermediate mass" black holes, or "objects much more massive than a typical star, but not quite as big as the supermassive black holes that inhabit the centers of galaxies," according to Nature.
It is not yet known in which galaxy this merger took place, but it was detected in the same region of the sky where a quasar was detected: an extremely bright galactic center powered by a super massive black hole — undergoing a flare around a month after the merger, though debate is ongoing whether the two events are related or not.
In April 2019, Scientists revealed the first true image of a black hole, captured and released by the Event Horizon Telescope (EHT) collaboration and streamed live by the US National Science Foundation.