Thursday, November 21, 2013

Supermassive Black Holes.

For a long time, Black Holes have only existed in the realm of scientific theory. Astronomers have long suspected unique and peculiar forces of nature behind the formation of universe but there has been not any scientific proof that clearly explained how galaxies are formed.  However, one of the most important discoveries in astronomy was made in June 2000 when scientists discovered the Supermassive Black Holes (BBC).  This was one of the most promising discoveries that would help in answering a number of questions in cosmology, most important in explaining how galaxies are formed.  Supermassive Black Holes give the ultimate answer to the question of how and from where do galaxies arise from.  Scientists now believe that the forces of pure destruction encoded in Supermassive Black Holes give rise to galaxies which means they are at the heart of the creation of stars, planets and ultimately all life forms in the universe.

Supermassive Black Holes are quite extraordinary such that for a long time, many people have doubted their existence. The basic idea behind the Supermassive Black Holes was considered more like fiction than reality due to the fact that these holes are almost the size of the solar system (BBC 2000).  On the base of their size, it was presumed that they would just destroy the basic fabric that holds the universe together.  However, these assumptions have changed in the last five years owing to a number of discoveries that have expanded scientific understanding of Supermassive Black Holes and how they help in the formation of galaxies.

One of the main factors that have delayed and inhibited scientific understanding of the Black Holes for a long time has been the fact that Supermassive Black Holes are very large to an extent that they swallow in any light, which means it is quite difficult to see them.  For a long time, astronomers have been using very power Hubble Space Telescope looking into each and every galaxy to see if they can find any meaningful information on Supermassive Black Holes. Since it has become difficult to see these Holes, scientists have now been looking for the basic effects of the massive gravity which hurls stars around them at an immense speed (Melia 34).  On basis of search for their immense power, scientists have discovered more Supermassive Black Holes exist in each and every galaxy. They have been considered massive giants of destruction and can be spotted in the entire universe. This implies that Supermassive Black Holes are part and parcel of galaxy and they are actually important in their formation.

Observing a galaxy using a powerful telescope reveals that there is a giant black hole of apocalyptic proportions that lurks in each and every galaxy, including our own and even the Milky Way.  Scientific work reveals that at the heart of every galaxy, there is a large Black Hole that is larger, three billion times the size of the sun (Melia 34).  A single black hole is considered to be more powerful to an extent that it can destroy the whole solar system.  Further scientific researches also reveal that Supermassive Black Holes tend to suck stars and gas, which are the heart of every galaxy.

Evidence of Supermassive Black Holes
Supermassive Black Holes have been indicated and illustrated in various telescope and X-ray images taken from different galaxies.  The following image shows Supermassive Black Hole

It has also been observed that the strongest evidence to date of Supermassive Black Holes is that of Sagittarius A.  The evidence based on the data from ESO and Keck Telescope reveals that the Earths galactic central hole can be calculated to be 4.1 million solar masses. It has been generally accepted that every galaxy contains a Supermassive Black Hole (Melia 34).  The mass of this hole and the velocity of dispersion of the galaxy provide an important correlation through M-sigma relation which gives strong indication that the black hole could give rise to galaxies. More evidence on existence of Supermassive Black Holes was presented on January 2010 during American Astronomical Society meting by Jule Comerford from University of California who showed images taken using W.M Keck Observatory and Hubble Space Telescope which shows 33 merged galaxies containing Supermassive Black Holes.

How is Supermassive Black Holes formed

Currently, there is little understanding of the process behind the formation of the Supermassive Black Holes. There are number of theories that have been postulated to explain the process of formation.  One of the models is based on the slow accretion of matters which starts from black hole barely the size of the stellar.  Another model is based on large gas cloud which collapses into relativistic star the size of hundred thousands solar masses (Begelman 2006, p. 290). Owing to radial perturbation, the star could become unstable and eventually collapse into a black hole even without any explosion. Another model argues that they could be formed from dense stellar cluster which undergoes core-collapse due to negative heat capacity in the solar system that drives velocity dispersion.

However, most scientists have supported the idea that Supermassive Black Holes are formed from primordial black holes originating from the Big Bang. It has been postulated that about 200 million years after the Big Bang, the universe had changed greatly and it was a quite different place (Begelman 2006, p. 295).  This was a period which could be described as dark ages as there were no stars and no star light. The first star, Population III stars, could have been formed when hydrogen and helium cooled enough to clamp together, which means they then collapsed and initiated a nuclear fusion. At the time when the stars were being formed, the universe was full of dark matter which could have fueled the formation of stars. These stars could have provided the base for formation of Supermassive Black Holes as they swallowed large quantities of matter over a period of millions of years.  There has been theoretical proposition of a gas cloud collapsing and forming a Supermassive Black Holes (Begelman 2006, p. 292).  It has also been postulated that there was a possibility of star-like black holes merging together to form a massive black hole. 
                      
The picture above shows NGC 624, which is a galaxy found 400 million light years from the Milky Way.  In the picture which was taken from Hubble Space Telescope and Chandra X-ray Observation, two black holes are coming close to one another and in millions of years, they are expected to merge and form one Supermassive Black Holes after the dust has settled.

What is the implication of Submassive Black Holes

There has been important question on how the giant black holes will affect the galaxies around Earth.  This question has startled most astronomers but recent research shows that while they are quite destructive, they may be important in creation of galaxies which they themselves live in.  Scientists have for long not found any explanation on how gases condensed to form the universe we live in but Supermassive Black Holes could be an important link that will assist them in order to explain cooling of these gases (BBC 2000). The gravity of Supermassive Black Holes could trigger cooling of gases while churning of gases could give rise to new stars, planets, and even life. While Supermassive Black Hole in our galaxy could be the reasons why we are alive, it could also pose a great danger. Scientists have shown that in 3 billion years, our galaxy could collide with the neighboring galaxy, Andromeda which may result in apocalypse force that will throw Earth out of the solar system (BBC 2000).

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