Scientists from the University of Cape Town in South Africa have recently released a report detailing the discovery of three monstrous black holes clumped together in a distant galaxy. Discovery of these black holes suggests that closely-packed groups of black holes are much more common than we previously thought.
Black holes are regions in space with such high gravity that nothing, not even light, can escape from them. Supermassive black holes are the largest type and their masses can be millions to billions times greater than the sun.
Most galaxies, perhaps all galaxies, are thought to contain at least one supermassive black hole at their centers. Our own Milky Way galaxy is believed to have a supermassive black hole 26,000 light-years away from our Solar System. However, these new findings provide evidence that galaxies can contain multiple black holes.
Galaxies are capable of evolving by merging together. When two galaxies draw close together, their gravities can cause the two to merge and become one large galaxy. Since each galaxy has its own supermassive black hole at its center, it would be reasonable to expect that the resulting merged galaxy winds up with two black holes. However, finding pairs of black holes is much harder in practice than in theory. It is theorized that black holes may fuse together to form a single black hole. Additionally, some black holes orbit each other so closely that it is hard tell the difference between the two.
Scientists discovered this trio of black holes by using VLBI (Very Long Baseline Interferometry). VLBI uses signals from radio telescopes separated by 10,000 KM to see details that even the Hubble Space Telescope couldn’t catch. Keith Grainge, a member of the research team, tells the news team at the University of Manchester about VLBI:
“This exciting discovery perfectly illustrates the power of the VLBI technique, whose exquisite sharpness of view allows us to see deep into the hearts of distant galaxies. The next generation radio observatory — the Square Kilometre Array — is being designed with VLBI capabilities very much in mind.”
The research team was very excited to find the black holes, especially since only four triple black-hole systems have ever been discovered. Roger Deane, the lead author of the report, tells National Geographic, “We were quite surprised to find it.”
Astronomers hope that this discovery will lead to further insight into how gravity behaves in extreme conditions. Their goal is to find out more about the elusive gravitational waves that ripple through space-time.
[Image via NASA/CXC/UCLA/Z.LI AND NRAO/VLA]