A team of researchers has uncovered evidence of an “intermediate-mass” black hole that is being hailed for being not too big and not too small.
(CN) — Long rumored to exist but never found, scientists have discovered a new type of black hole that is noteworthy not for being among the biggest or smallest of black holes, but for being in-between.
Few objects in the dark reaches of the cosmos have captured the fascination and imagination of scientists quite like black holes. First definitively discovered in the 70s, black holes are bodies of space that command such strong gravitational pulls that nothing — not even light itself — can escape from it, and researchers have long sought to explore the untold mysteries that surround their existence.
One aspect of black holes that has garnered particular attention among scientific circles is how they can vary so wildly in size. This is because they are typically lumped into two categories: stellar-mass black holes and supermassive black holes. Stellar-mass black holes tend to be smaller beings, typically around 10 to 100 times the mass of our sun, while supermassive black holes can reach sizes up to a billion times the size of our sun and can serve as some of the largest known objects in the universe.
Due to this tremendous discrepancy in size between these two types of black holes, researchers have long theorized that there exists what they call the intermediate-mass black hole. These types of black holes would act as a kind of bridge between the two sizes, as they would be far bigger than the comparatively tiny stellar-mass black holes but not nearly as shockingly large as the supermassive variety.
The problem with these “goldilocks” black holes is that experts have never actually been able to find one — until now.
In a study published Monday in Nature Astronomy, researchers from the University of Melbourne and Monash University in Australia reveal that they have discovered a black hole roughly 55,000 times the mass of our sun, a size that fits perfectly into what researchers long guessed an intermediate sized black hole would look like.
On top of confirming the existence of a new classification of black holes, experts say they believe that this discovery could help them understand how some black holes can balloon in size. Researchers think these average sized black holes may even be cosmic seeds, of sorts, that supermassive black holes are ultimately formed from.
“While we know that these supermassive black holes lurk in the cores of most, if not all galaxies, we don’t understand how these behemoths are able to grow so large within the age of the Universe,” James Paynter, University of Melbourne PhD student and lead author of the study, said in a statement.
Experts say they discovered this new black hole through a large gamma-ray burst in the reaches of space that alerted them to this new body. The gamma-ray burst, lasting no longer than half a second, came as a result of two distant stars merging together and when experts observed the resulting light energy, they noticed that it came with a strange echo. The echo, they determined, was the work of their newly discovered black hole that bent the light so completely they were actually able to observe it twice.
From there, the scientists were able to use complex software to confirm that they were witnessing not just the influence of a black hole, but a black hole that fell within the long-fabled intermediate size zone.
Experts say that with this new discovery, they believe they have the information they need to calculate just how many of these goldilocks black holes are out there. Using the data from this singular object, researchers say there may be around 46,000 other black holes just like it around the Milky Way alone.
Rachel Webster, from the University of Melbourne and co-author on the study, says this crucial discovery has been a long time coming and represents a tremendous leap forward in our understanding of these mysterious cosmic giants.
“Using this new black hole candidate, we can estimate the total number of these objects in the Universe,” Webster said. “We predicted that this might be possible 30 years ago, and it is exciting to have discovered a strong example.”