Some of the oldest star clusters in the known universe should not contain black holes, at least according to modern theories. However, a team of astrophysicists have recently discovered black holes in these groups of stars, challenging what we now know about these clusters and where and how black holes develop.
These globular star clusters could have possibly up to tens of millions of stars that can collide with each other. Because of this, it was originally thought that any black holes that formed in a cluster would be ejected. Scientists believe that these stars are continuously playing bumper cars with each other and slinging black holes out of their area until they no longer exist. However, scientists recently discovered black holes in these clusters, disproving 40 years of theories.
The first such black hole was located in 2007 in the NGC4472 galaxy. This one was found by viewing an X-ray emission that showed gas going into the black hole and getting extremely hot. After that, other black hole discoveries in globular star clusters followed using radio telescopes. Once a black hole eats a star, it throws out material that sends out radio emissions. The telescope detects that material through its frequency. This year alone, two such black holes in star clusters were discovered this way in our own galaxy. Scientists believe no other explanation for those radio emissions is valid: they must be black holes.
Things could get even more exciting because of these new discoveries. Because these stars do exist in clusters, their black holes could theoretically get close enough to come together to form a bigger black hole. And those giant black holes could create "ripples in space-time" and could provide the ultimate test of Einstein’s theory of relativity. In other words, these new black holes could confirm or change what we know about physics.
Via Texas Tech