In recent years, there have been made more and more discoveries about black holes. While what we ended up knowing about them is quite extensive, we realize that black holes still remain a mystery.
A short while ago, a new kind of black hole was discovered. It is a ‘middleweight’ black hole, and it is quite rare. This unique black hole is 2,200 bigger than the sun and was detected in the globular cluster 47 Tucanae (NGC 104) of the Tucana constellation. Until now, astronomers had found ‘small’ black holes which can be just slightly bigger than our sun, but also supermassive black holes, which can be billion times bigger than our sun.
First hypotheses and theories on black holes
Almost 250 years ago, there had been speculations about ‘dark stars’ what had so high a density that light could not break away from its gravitational attraction. The one that came with this theory was John Michell, an English natural theorist who contributed with pioneering observations in astrophysics, geography, optics, and gravitation.
The next person to bring forth his observations about black holes was Albert Einstein. Karl Schwarzschild and Johannes Droste closely followed him. They all used mathematics to compose theories about the existence of former massive stars that became something else entirely.
Their theories and discoveries were certified centuries later when, with the help of powerful telescopes, astronomers and astrophysicists caught images of the famous black holes.
Properties of black holes
Black holes have a fantastic density. Our sun has a thickness of 1, 41g/cm3. If the sun would collapse and turn into a black hole, it would get to have around twenty billion tonnes/cm3. The gravitational attraction a black hole has is powerful. In 1958 it was discovered the ‘event horizon’ of black holes, which is the zone around a black hole that, once passed, nothing can return.
There were many theories about black holes. One of these claimed that the opposite of a black hole is a white hole. Igor Novikov believed that if matter enters a black hole, it can come out through a white hole.
The theory of black holes being portals to other places or dimensions was widely used not only in astrophysics but also in literature and media, such as stories, novels, TV-series, films, etc. Conclusively, the notion of ‘black hole’ is yet to be understood. Is it a portal? Can you time-travel if you enter one? What is beyond the ‘event horizon’ of a black hole? There are so many questions that still remain unanswered. But the only thing that we know for sure is that black holes still keep us captivated.