FROM STELLAR GRAVEYARDS TO SUPERMASSIVE GIANTS : A LOOK AT BLACK HOLE TYPES

              Stellar black holes, Super massive black holes, and Intermediate black holes are the 3 categories of black holes that astronomers have so far identified.

STELLAR BLACKHOLES : LITTLE BUT LETHAL 

               A star may collapse or fall into itself when it has used up all of its fuel. The new core of smaller stars (those with masses up to around 3 times that of sun.) will eventually transform into a neutron star or white dwarf star. But as a bigger star disintegrates, It keeps getting smaller and smaller until it forms a stellar black hole.

              Black holes created when individual stars collide are comparatively small but immensely dense. One of these objects has a diameter of a city and more than 3 times the mass of sun. As a result, the gravitational attraction on objects nearby is extremely strong.  The gas and dust from the surrounding galaxies are then ingested by stellar black holes, which keeps them contracting in size.

STELLAR MASS BLACKHOLE

   SOURCE: NASA

SUPERMASSIVE BLACKHOLES-THE BIRTH OF GIANTS 

              Although there are many little black holes in the cosmos, Supermassive black holes predominate. Although they are millions or even billions of times more massive than the sun, the diameter of these giant black holes is around the same. It is hypothesized that such black holes, including the Milky way , are in the center of almost every galaxy.

Sagittarius A* - A supermassive black hole 

A Super massive blackhole. Source : NASA

             The origin of such massive black holes remains a mystery to scientists. Once these giants have created , they continue to increase in size by absorbing mass from the gas and dust that surround them, which is abundant in the center of galaxies.

              Its possible that hundreds or thousands of microscopic black holes merge to form supermassive black holes. Large gas clouds that collide and quickly accrete mass cloud possibly be to blame. A stellar cluster collapsing or a collection of stars collapsing at once is a third possibility. Fourth, vast collections of dark matter may give rise to supermassive black holes. We  able to directly detect this substance through its gravitational pull on other things , but we are unable to directly observe dark matter, hence we do not know what it is made of.

INTERMEDIATE BLACK HOLES 

              Research has shown that midsize or Intermediate black holes(IMBHs)may exist. Previously, scientists believed that black holes only occurred in tiny and large sizes. Such bodies might develop as a result of repeated collisions between stars in a cluster. If several of these IMBHs develop in the same aera, they might eventually collide to generate a supermassive black hole in the galaxy's center.

              In the arm of a spiral galaxy in 2014, Scientists discovered what seemed to be an intermediate mass black hole. And in 2021 astronomers used an old gamma-ray burst to their advantage to find one.

INTERMEDIATE BLACK HOLE 

ATTEMPT FROM NASA TO CAPTURE THE INTERMEDIATE BLACKHOLE.

Source : NASA

              Astronomers have been working very hard to find these medium-sized black holes, According to research co-author Tim Roberts of the university of Durham in the United Kingdom. "There have been hints that they are out there, but IMBHs have been acting like a long-lost relative who doesn't want to be found".

             According to research published in 2018, these IMBHs may be found at the center of dwarf galaxies or other small galaxies. X-ray activity, which is typical of black holes, was detected in observations of 10 such galaxies, five of which were previously unknown to science before this most recent survey. This suggested the existence of black holes with masses ranging from 36,000 to 316,000 solar masses. The Sloan digital sky survey which studies around a million galaxies, provided the data. It is capable of detecting the type of light that is frequently seen emanating from black holes that are capturing surrounding debris.

BINARY BLACKHOLES - THE DOUBLE TROUBLE

             Astronomers discovered gravitational waves from merging star black holes in 2015 using the Laser Interferometer Gravitational Wave Observatory (LIGO).

             The LIGO scientific collaboration (LSC) released a statement through a spokesperson named David shoemaker "we have further confirmation of the existence of stellar mass black holes that are larger then 20 solar masses . These are objects we didn't know existed before LIGO detected them" he stated. The measurements made by LIGO also shed light on the direction of a black holes rotation. Two black holes can spin in the same direction or the opposite direction as they spiral around one another.

            Two ideas exist above the formation of binary black holes. According to the first theory, 2 stars that were born together and died violently at roughly the same time gave rise to 2 black holes that formed in a binary at or near that same moment. The 2 black holes that were left behind would have shared the same spin orientation as the companion stars.

            According to the second hypothesis, two blackholes in a star cluster merge in the cluster's center.

According to LIGO Scientific Collaboration, these companions would have unpredictable spin orientations when compared to one another. This creation scenario is supported by LIGO's discoveries of companion black holes with various spin orientations.

Credit: NASA's Goddard Space Flight Center/Scott Noble; simulation data, d'Ascoli et al. 2018

          "We are starting to gather real statistics on binary black hole systems" said CalTech LIGO scientist Keita Kawabe, who is located at the LIGO Hanford Observatory. That's intriguing since, even at this point, some black hole binary creation theories are slightly preferred over the others . Hopefully, we can further refine this in the future.

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