A team of international experts who normally try to debunk the existence of black holes has turned over a new leaf. The team, including Kareem El-Badry — known by many as the “black hole destroyer” — discovered a dormant black hole outside the Milky Way. The discovery is not only a first for the team but also challenges everything we thought we knew about the formation of black holes.
A dormant black hole discovered outside the Milky Way
Astronomers believe that stellar-mass black holes form when the core of a massive dying star collapses. Many also believe that these collapses are accompanied by a supernova explosion. These explosions can help us find newly formed black holes in the first place. But this new discovery appears to be a dormant black hole based on astronomers’ data.
“For the first time, our team got together to report on a black hole discovery, instead of rejecting one,” Tomer Shenar, lead author of a study published in Nature Astronomy, says. (via Phys.Org) The team says that other candidates have been proposed as the first “dormant” stellar-mass black hole. However, this is the first time one has been unambiguously detected outside our own galaxy.
A stellar-mass black hole forms when a massive star reaches the end of its life. At that point, the star collapses under the weight of its own gravity. If the black hole happens to be in a binary system, where two stars revolve around each other, then the black hole begins to orbit the other star. However, most black holes remain active, feeding off other objects and emitting high X-ray radiation levels.
Active or dormant?
For a black hole to truly be “dormant,” it cannot emit high levels of X-ray radiation. This is a bit of an enigma and a big problem for black hole hunters. That’s because we use those high levels of X-ray radiation to track and detect the black holes. Despite the strict requirements they need to meet, many astronomers believe that dormant black holes are very common.
However, we have yet to find many of these mysterious cosmic entities. In fact, this is the first dormant black hole we’ve discovered outside of our galaxy. The discovery was only possible thanks to six years of observations captured by the European Southern Observatory’s Very Large Telescope.
As we discover more dormant black holes, we may learn more about what causes these massive cosmic objects to interact with the world as they do. And, perhaps, we could even learn more about the supermassive black hole that lies at the center of our own galaxy.