The most stealthy monsters are often the most interesting.
And most stellar-mass black holes are silent monsters, floating invisibly through the great abyssal depths of space, showing no sign except the curvature of light via photons straying too close. This has forced astronomers to look for other ways to detect them, such as stars that appear to be locked in a strong binary orbit with what appears to be nothing at all.
And, for the first time, astronomers have successfully identified a black hole beyond our galaxy using this unconventional technique, according to a recent study published in the journal Monthly notices from the Royal Astronomical Society.
This could become a crucial step in revealing the evolution of black holes inside and outside our Milky Way.
How to spot a stellar mass stealth black hole
The suspicious movements of an orbiting star have revealed a black hole of comparable size in the Large Magellanic Cloud, which is a dwarf galaxy orbiting our own, about 160,000 light years away. Called NGC 1850, the black hole was found in a star cluster called NGC 1850 (celestial mapping is a logical practice), which contains thousands of stars. This recent detection suggests that the method could be crucial in finding black holes in densely populated star clusters, both within and beyond our enormous Milky Way. “Similar to Sherlock Holmes stalking a criminal gang from their missteps, we look at every star in this cluster with a magnifying glass in one hand trying to find evidence of the presence of black holes but not seeing them directly,” Sara said. Saracino, an astrophysicist at John Moores University in Liverpool, UK, in a report by Scientific alert.
“The result shown here is only one of the wanted criminals, but when you have found one you are on your way to finding many more, in different groups,” added Sarecino. The majority of the black holes listed so far beyond our Milky Way were easy to spot, as they launch inadmissible volumes of deadly radiation, meaning they actively suck up indescribable scales of matter, which are the real thing. source of radiation (since the black holes themselves reveal virtually nothing). Astronomers have identified more black holes via gravitational waves since the first were detected in 2015. This is when subtle ripples in the very fabric of spacetime are thrown in our direction as a result of a violent collision of two black holes. But despite all of our progress, these mapped black holes aren’t even the tip of the cosmic iceberg.
Baby black holes are waiting for us
There could be 100 million stellar mass black holes in our galaxy alone. Obviously, we have a lot more to do. And that also means that we have a lot to learn about those seemingly evil maws in the ancient depths of the darkest corners of the galaxy. But we don’t need to look them in the face to understand their properties, because the things they take with them, like gravitationally trapped stars, will reveal their secrets by the way they move.
Hundreds of thousands of light years away, these stars appear to be motionless. But the light of the stars themselves will change, its wavelength stretching and compressing as the solar oven moves closer and further away from us. And then we know they’re in the grip of a black hole. Continuing to study black holes in young star clusters could reveal more about how colossal stars and neutron stars are forged in the black holes we know and fear. And, since many of these star clusters are very young – NGC 1850 is only 100 million years old – it is possible to discover young black holes, which would provide a unique window into their complex and haunting evolution.