THE DARK GIANTS OF THE UNIVERSE
THE DARK GIANTS OF THE UNIVERSE
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ABSTRACT
ABSTRACT
In this dark universe, there lies a dark supergiant containing tremendous energy and power to engulf anything around it. The cosmic narrative unfolds with the mysterious presence of black holes, celestial entities born from the gravitational collapse of massive stars or the fusion of smaller counterparts. This paper explores the fundamental characteristics, formation mechanisms, and diverse types of black holes, encapsulating their enigmatic nature that challenges our comprehension of the universe. It discusses the relation of black holes with dark matter and its necessity for a stable galaxy, whereas the observations let us know the outcomes of matter under the influence of a black hole.
In this dark universe, there lies a dark supergiant containing tremendous energy and power to engulf anything around it. The cosmic narrative unfolds with the mysterious presence of black holes, celestial entities born from the gravitational collapse of massive stars or the fusion of smaller counterparts. This paper explores the fundamental characteristics, formation mechanisms, and diverse types of black holes, encapsulating their enigmatic nature that challenges our comprehension of the universe. It discusses the relation of black holes with dark matter and its necessity for a stable galaxy, whereas the observations let us know the outcomes of matter under the influence of a black hole.
KEYWORDS: Event Horizon, Supernovae explosion, Singularity, Hawking Radiations.
KEYWORDS: Event Horizon, Supernovae explosion, Singularity, Hawking Radiations.
INTRODUCTION
1.1 In the cosmic tapestry of our universe, few phenomena evoke as much fascination and intrigue as black holes. These enigmatic entities, born from the gravitational collapse of massive stars or the merger of smaller counterparts, challenge the very fabric of spacetime and stretch the limits of our understanding of the universe. Black Holes may be defined as A region of spacetime from which nothing, not even light, can escape, because gravity is so strong. A black hole’s surface, called its Event horizon, defines the boundary where the velocity needed to escape exceeds the speed of light, which is the speed limit of the cosmos.
1.1 In the cosmic tapestry of our universe, few phenomena evoke as much fascination and intrigue as black holes. These enigmatic entities, born from the gravitational collapse of massive stars or the merger of smaller counterparts, challenge the very fabric of spacetime and stretch the limits of our understanding of the universe. Black Holes may be defined as A region of spacetime from which nothing, not even light, can escape, because gravity is so strong. A black hole’s surface, called its Event horizon, defines the boundary where the velocity needed to escape exceeds the speed of light, which is the speed limit of the cosmos.
1.1.1 How Black Holes are formed?
1.1.1 How Black Holes are formed?
Most black holes form from the remnants of a large star that dies in a supernova explosion*. Smaller stars become dense neutron stars, which are not massive enough to trap light. If the total mass of the star is large enough (about three times the mass of the Sun), it can be proven theoretically that no force can keep the star from collapsing under the influence of gravity. However, as the star collapses, a strange thing occurs. As the surface of the star nears an imaginary surface called the "Event Horizon", time on the star slows relative to the time kept by observers far away. At the core of a black hole lies a point of infinite density known as a Singularity.
Most black holes form from the remnants of a large star that dies in a supernova explosion*. Smaller stars become dense neutron stars, which are not massive enough to trap light. If the total mass of the star is large enough (about three times the mass of the Sun), it can be proven theoretically that no force can keep the star from collapsing under the influence of gravity. However, as the star collapses, a strange thing occurs. As the surface of the star nears an imaginary surface called the "Event Horizon", time on the star slows relative to the time kept by observers far away. At the core of a black hole lies a point of infinite density known as a Singularity.
1.1.2 Accretion Disk
Matter falling toward a black hole forms an accretion disk, a swirling mass of gas and dust that becomes superheated and emits various forms of electromagnetic radiation, including X-rays.
Credits: Circumbinary Accretion: From Binary Stars to Massive Binary Black Holes
1.2 Identification of Black Holes in Space
Nothing can escape black holes, thus the question arises how the presence of black holes is detected. The telescope searches the environment to the surrounding areas, as the matter is heated to really high temperatures (in million degrees), due to which X ray radiation is transmitted. These rays are then detected by the telescope.
1.3 Types of Black Holes
Black Holes are broadly classified on the bases of formation and size. The categories are as follows:
1.3.1 Stellar Mass Black Holes
these are born from the death of stars much more massive than the Sun. When some of these stars run out of the nuclear fuel that makes them shine, their cores collapse into black holes under their own gravity. Other stellar mass black holes form from the collision of neutron stars. These are probably the most common black holes in the cosmos, but are hard to detect unless they have an ordinary star for a companion. When that happens, the black hole can strip material from the star, causing the gas to heat up and glow brightly in X-rays.
1.3.2 Supermassive Black Holes
found at the centres of nearly every galaxy. They range in mass from 100,000 to billions of times the mass of the Sun, far too massive to be born from a single star. The Milky Way’s black hole is about 4 million times the Sun’s mass, putting it in the middle of the pack. In the form of quasars and other galaxies, these black holes can shine brightly enough to be seen from billions of light-years away. Understanding when these black holes formed and how they grow is a major area of research.
1.3.3 Intermediate Black Holes
They weigh 100 to 10,000 times the mass of the Sun, putting them between stellar and supermassive black holes. Since we’ve hardly seen any of them yet we don’t know exactly how many of these are, and like supermassive black holes, we don’t fully understand how they’re born or grow.
1.4 Death of Black Holes
Late scientist Sir Stephen Hawking proposed that the black holes are not completely black but emit a small amount of thermal radiation known as Hawkings Radiations due to quantum effects occurring near the event horizon. But even for a small black hole, it will require millions of years to its death.
PHYSICS FOR MATTER AROUND BLACK HOLES
There are various changes in the quantities associated with matter. Few are listed as follows
2.1 Variation in temperature
As the particle gets closer to such a huge mass, it accelerates at a very high rate, due to the friction caused by the star dust or other particles, the body heats up to millions of degrees.
2.2 Time Dilation
The mass of black holes distorts the space time curve due to which the time for an object near black hole moves really slow. Theoretically time is assumed to be still at the event horizon.
2.3 Spaghettification
the immense gravity of the black hole compresses matter horizontally and stretches vertically like a noodle, this phenomenon is termed as spaghettification.
RELATION OF BLACK HOLES AND DARK MATTER.
The question arises about the existence of galaxies with central collapsing objects. A black hole is a process of unlimited compression (collapse) of matter under the action of dominant forces from its own gravitational field. In this case, the density grows indefinitely, and the energy per particle inevitably reaches and exceeds the binding energy of “elementary” particles in neutrons, or in their composite components. Due to this the galaxies must have collapsed. In the macroscopic theory of dark sector, the contribution to the galaxy rotation curves by dark matter, described by a longitudinal vector field, is expressed in terms of the non-zero covariant divergence of the field at the centre(𝜑) which in return depends on the interaction of dark matter with a black hole in the centre of a galaxy. This interaction is the ultimate reason for the stable galaxies even after the presence of supermassive black holes as its centre
DISCOVERED BLACK HOLES AND THEIR OBSERVATIONS
Till date, many black holes have been discovered and the number is still increasing. Out of which here are the few Black holes and their characteristics.
1.Sagittarius A (Sgr A*): It is classified as a supermassive black hole at the centre of our milky way galaxy with a mass equivalent to approximately 4 million times that of our Sun. Despite its formidable mass, Sagittarius A occupies an exceedingly compact space, with a radius estimated to be less than 0.002 light years. It is just 26000 ly away from Earth.
Credits: Nasa
2. Cygnus X-1 (Cyg X-1): It is one of the brightest X-ray sources seen from Earth. Cyg X-1 has since been found to be a binary system consisting of a blue supergiant star and a companion, which is likely a black hole. In fact, Cyg X-1 has the distinction of being the first object identified as a black hole. The black hole's companion is a blue supergiant
CONCLUSION
The exploration culminates in a comprehensive understanding of black holes as cosmic entities,revealing their diverse types, intriguing physics, and intricate relationships with dark matter.This knowledge not only expands our comprehension of the universe but also underscores the crucial role black holes play in shaping the cosmic landscape.
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