US, WASHINGTON (ORDO NEWS) — How are Black Holes formed and what are they?
Star black holes are small but deadly.
When a star burns through the remnants of its fuel, it can collapse or fall into itself. For smaller stars (up to about 3 times the mass of the Sun), the star will become a neutron star or a white dwarf. But when a large star falls into itself, it continues to shrink and creates a starry black hole.
The black holes formed during the collapse of stars are relatively small, but incredibly dense. One of these objects is three times the mass of the sun fits into the diameter of the city. This results in a crazy amount of gravitational force attracting objects around the object. After formation, stellar black holes begin to absorb dust and gas from the galaxies surrounding them, which allows them to grow in size.
According to the Harvard-Smithsonian Center for Astrophysics, the Milky Way contains several hundred million stellar black holes.
Supermassive black holes – the birth of giants
Small black holes inhabit the universe, but their cousins, supermassive black holes, dominate. These huge black holes are millions or even billions of times more massive than the Sun, but their diameter is about the same. It is believed that such black holes lie in the center of almost every galaxy, including the Milky Way.
Scientists are not sure how such large black holes appear. Once these giants have formed, they begin to gather mass from dust and gas around them, material that is abundantly located in the centers of galaxies, allowing them to grow to even larger sizes.
Supermassive black holes can be the result of a merger of hundreds or thousands of tiny black holes. Large gas clouds can also be responsible for this process, collapsing together and rapidly gaining mass. The third option is the collapse of a star cluster, a group of stars falling together. Fourth, supermassive black holes can arise from large clusters of dark matter. This is a substance that we can observe due to its gravitational effect on other objects; however, we do not know what dark matter consists of, because it does not emit light and cannot be directly observed.
Intermediate black holes – stuck in the middle
Scientists once thought that black holes are only small and large, but recent studies have revealed the possibility of medium or intermediate black holes (IMBH). Such bodies can form when stars in a cluster collide. Several such intermediate black holes that form in the same region can ultimately come together in the center of the galaxy and create a supermassive black hole.
In 2014, astronomers discovered something similar to a medium-sized black hole in the sleeve of a spiral galaxy.
“Astronomers have been very diligent in looking for these medium-sized black holes,” said study co-author Tim Roberts from Durham University in the United Kingdom. “There were hints that they exist, but they behave like a long-lost relative who is not interested in being found.”
New research conducted in 2018 showed that these intermediate black holes can exist in the heart of dwarf galaxies (or very small galaxies). Observations of 10 such galaxies (five of which were previously unknown to science before this last study) revealed X-ray activity – common for black holes – indicating the presence of black holes weighing from 36,000 to 316,000 suns. The information came from the Sloan Digital Sky Survey telescope, which studies about 1 million galaxies and can detect those signals that often come from black holes collecting nearby material from dust and gas.
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