No matter how much we learn about the mysteries of black holes, many questions remain about these enigmatic objects.
Now, scientists have discovered a massive black hole more than 8,200 times the mass of our Sun in a nearby star cluster, potentially unlocking the secrets of these voids.
Located at the heart of the Omega Centauri cluster, 18,000 light-years away, this super-dense object is the closest example of a massive black hole ever discovered.
Although it may look enormous, researchers at the Max Planck Institute for Astronomy and the University of Utah say it is just a medium-sized black hole.
Researchers say the first-of-its-kind discovery could provide a “missing link” in the mysterious evolution of black holes.
Scientists have discovered a massive black hole just 18,000 light-years from Earth that could be the missing link in the evolution of these strange objects.
Black holes form when extremely large stars collapse in on themselves as they use up the last of their fuel.
As stars fall inward, their remaining mass is compressed into an object so dense that not even light can escape its gravitational pull.
These objects range in size from “stellar black holes” of only a few times the mass of our Sun to truly enormous monsters called “supermassive black holes” with millions or billions of stellar masses.
Co-author Matthew Whittaker, an undergraduate at the University of Utah, says: ‘There are black holes a little bit heavier than our Sun that are like ants or spiders: they’re hard to spot, but they’re everywhere in the universe.
‘Then we have supermassive black holes that are like Godzilla in the center of galaxies tearing things apart, and we can easily see them.’
However, sSo-called “intermediate black holes” are extremely difficult to observe because galaxies tend to have only massive black holes at their centers.
Whittaker says: “These intermediate-mass black holes are in the same league as Bigfoot. Detecting them is like finding the first evidence of Bigfoot: people will freak out.”
Black holes form when massive stars collapse into dense objects that pull in everything around them. As they feed on surrounding matter, some become supermassive black holes like the one at the center of the Milky Way.
Researchers believe that the Omega Centauri cluster (pictured left) was once a galaxy of its own that was swallowed by the Milky Way. This makes it likely that there is a black hole (pictured right) at its center.
Fortunately, The unique history of the Omega Centauri cluster provided researchers with a perfect opportunity to find one of these rare items.
Scientists believe Omega Centauri was once a galaxy of its own that was absorbed into the Milky Way billions of years ago.
Stripped of its outer stars, the dense core of stars we can see through our telescopes is all that remains of what once formed the galactic core.
That made it extremely likely that there was a young black hole trapped at the heart of Omega Centauri, frozen in time like an insect in amber.
Unable to feed on surrounding stars, scientists predicted the intervening black hole would remain exactly the same as when the Milky Way first swallowed it.
To test this theory, researchers examined 500 images taken by the Hubble Space Telescope.
Although most of these images were taken simply to calibrate Hubble’s instruments, they allowed researchers to track the velocity of 1.4 million stars.
Using Hubble Space Telescope observations like this one, researchers identified seven high-velocity stars that are being pulled in by a black hole at least 8,200 times the mass of our sun.
Of those 1.4 million, scientists found seven stars right near the center that were moving at unexpectedly high speeds.
Dr Maximilian Häberle from the Max Planck Institute for Astronomy says: “Searching for high-velocity stars and documenting their motion was like looking for a needle in a haystack.”
Just a fast moving star would not have proven anything, since the rapid transit of the star could have been caused by several different factors.
However, the presence of seven rapidly moving stars in the same region is strong evidence that they are being pulled by the gravity of an extremely dense object.
By determining the velocities of these seven high-velocity stars, Dr. Häberle and his co-authors were able to pinpoint the likely mass and location of this hidden object.
As predicted, at least 8,200 solar masses, this object would likely be an example of the long-sought intermediate black hole.
This discovery could help explain how black holes like the one at the centre of our galaxy (pictured) get so big.
Co-author Dr Nadine Neumayer, also from the Max Planck Institute for Astronomy, says: ‘Previous studies had raised critical questions such as ‘Where are the high-velocity stars?’
“We now have an answer to that question and confirmation that Omega Centauri contains an intermediate-mass black hole.”
Researchers now plan to study the center of Omega Centauri in greater detail and have already secured permission to use NASA’s James Webb Space Telescope.
However, because of the black hole’s lower mass, high-velocity stars could take hundreds of years to complete a single orbit.
This means that a full study of this black hole could remain a task for future generations.