“When the gravitational potential, GM/R, exceeds the square of the speed of light, c² in a region of space-time, this region of space-time is called blackhole.” This statement has worthwhile quality because it is not dependent of the details of gravitational theories. The framework of Newtonian theory may apply it. A more acceptable definition of a black hole is provided by this, it states that a blackhole is any astronomical body whose escape velocity must exceeds the speed of light. Indeed, two centuries ago John Michell and Pierre-Simon de Laplace gave the same reason to explain black hole. Any spherical body of mass M confined within the critical radius RS must be a black hole.
Mystery Of the BlackHole
Black holes are known one of the strangest creations by nature, which are made of space-time only. Anything falling into a blackhole, including light, is forever gone from our universe. Existence of blackhole was predicted very long ago, but their existence has been observed recently throughout our own galaxy and other galaxies in the universe. According to the principle, by squeezing any object into tiny enough volumes, can be made into a blackhole. Even a rock can be made a black hole. After the fuel run out object starts to collapse and crushed itself into zero size. However, Einstein’s theory says that the remaining behind is object’s mass and gravity, in the form of an extreme distortion around the space and time. This severe alteration space and time is the black hole. The darkest black in the universe is the black hole: The black holes are always hungry and become bigger and bigger in size by swallowing every thing in their way. Even, no matter how powerful a light you fall on it, no light ever reflects back, because the light is eaten by the hole. A blackhole is a true “hole” in space: Anything that passed near the edge of the hole called the “horizon” of the hole – is gone from the universe into the hole forever. That’s why black holes are considered door from our universe to any other because even in principle, nothing inside a black hole can ever communicate with our universe again. However black holes are even more strange than that explained. Einstein’s theory tells that the flow of the time slows down as you get closer to a massive body, but time flow is faster for the body far from the object. The slowing of time is extreme, near a black hole. Time is stopped for an observer outside the black hole. For example, an object is being swallowed by the black hole is appeared as frozen in time at the edge of the hole. Where the real mystery lies Inside the horizon of a black hole. The flow of time itself creates the picture of falling objects into the centre of the black hole according to the Einstein’s theory. Still, we are unable to understand the mystery of the black hole at its very centre. It is predicted by the Einstein’s theory of gravity that time itself is destroyed at the centre of the hole: time ends abruptly there. Because this reason, a blackhole is sometimes seeming as the “reverse of creation.” But how or why time could end abruptly, no one knows. Gravitational theory of Einstein fails to explain at these tiniest scales and to describe the that what happened at centre of black holes, laws of nature must be found. Is another universe led by the inside of a black hole, as have speculated by some scientists? No one knows the reality. No direct experiment can be performed at to find out, even in principle, because black hole gives no information or evidence out of a itself even it can absorb any intensity of light or any huge amount of matter. Therefore, it so important to find and black holes study from the outside. While at the same time, we need to develop new theories by which we can predict more confidently that what is happening inside the black hole.
Some astronomers acknowledged the real existence of black holes but they gained very little information on their real nature with powerful instruments such as orbiting telescopes because they made very distant and indirect observations on black holes. The theoretical physicists were the next who, by using tools such as general relativity, quantum mechanics and higher mathematics, tried to penetrate more deeply into the blackhole mystery, they got a little bit more information, but not so much. Nevertheless, the outsiders can get some idea of what is happening inside a black hole by using numerical calculations such as those performed at the Observatoire de Meudon.
How BlackHole Is Formed
In a star fuel is burning due to nuclear reactions like fusion reaction in the sun, which are continuously consuming the fuel of star e.g., sun is burning 500 to 600 million tons of fuel every second.
Hydrogen fuel is converting into helium. So that’s kind is gone forever. In the sun’s case it will last about another 4 or 5 billion years. When it will run out of the fuel, then the gravity will take over the star will and star will start to collapse. When a massive star dies it leaves a small core behind it and if star is big enough that its core is 3 times more massive than the sun then gravitational force becomes very large over all forces, there is no known force even the rigidity of matter that will stop its collapsing. So, it collapses and collapse till these changes remaining core of died star into the blackhole. Because it collapses under its own gravity. This is called stellar mass black Hole. They Can Also Form Directly From Very Big Stars.
Can We Destroy a Black Hole?
As black hole is the one the strangest creation in our universe and it is also most stable entity in the universe. The black hole is always hungry and grows in size bi eating everything becomes near it surface even nuclear bomb is unable to work on it. That’s why they are depicted as the ultimate destroyers in the universe always because they are capable of consuming everything in their path. But what will be the consequences if attempt is made to destroy this most stable black hole? what will happen by pushing the limits of physics? Can black holes be ripped apart. Can we destroy a blackhole?
Methods To Destroy a Black Hole
Let’s imagine a tiny black hole to explore this procedure. There are various methods to destroy a black hole. We can explore these various methods by imagining a tiny blackhole, created in lab with mass approximately equal to mass of moon.
Nuking The BlackHole
In nuking the black hole uses an extreme approach in which extremely large energy is produced by availing all the nuclear arsenal of the world entirely. If we will succeed in producing such huge amount of energy then two important questions arise. First question is that would it have any effect on the blackhole? And second main question is about the consequences of this immense energy on our earth and universe. As the black holes are the best absorber of matter and energy of huge intensity that crosses their event horizon. As by Einstein mass- energy equation can be converted into energy and vice versa. So, according to Einstein’s theory mass and energy are equivalent. Because
E = mc²
No matter how much immense energy is fall on blackhole, no light will reflect back towards the observer but all the energy is swallowed by the black hole. So, the mass of the black hole simply will increase due to all energy from the nuclear explosions. As a result, the black hole would become more massive and bigger than before. Instead of destroying it , the amount of energy is disappeared forever from the universe.
Annihilation With an Anti-Black Hole
The process in which particle and anti particle obliterate each other and disappears in form of energy given out electromagnetic radiation e.g., gamma rays, this process is called annihilation of matter. What happened if we attack black hole with antimatter? Would an anti- black hole will annihilate the hole? This might seem like plausible strategy because matter and antimatter annihilate each other. However, the distinction between matter and antimatter is erased one the enters in its event horizon. Whether moon or an anti-moon thrown and trapped into the black hole, the result would have no difference but same for both—the only outcome would be growth in size and mass the black hole. Black holes are independent of type of the matter they absorbed but only care about the total mass-energy.
The properties of matter, similar to elementary particles like electrons which given by just three characteristics: mass, spin, and charge, are deleted completely by a black hole. But surprisingly, same characteristics are shown by the black hole. No matter black hole is formed whether by a star, anti-star or anything. Once it is formed, its mass, spin, and charge are enough to fully describe it.
The Anti-Black Hole
As particle and anti particle have same but only difference is due to opposite charge on anti particle and coexistence for both is not possible but annihilate each other and disappears as energy. If want to destroy a blackhole with annihilation then we should consider the idea of an anti-black hole. As the distinction between matter and antimatter is its opposite charge. So, a black hole and anti-black hole would carry opposite charges according to the theoretical Physics. But again question arises that what would be the outcome if collision take place between them But? It’s answer is that their charges would cancel by each other and a massive and neutral black hole will remain behind. We would end with an even larger one, instead of destroying it.
Destroying The Event Horizon
When a blackhole comes to spin and charge, it has some limitations. The boundary beyond which nothing can escape gravitational pull of the black hole, even light can escape, this boundary is called event horizon. The event horizon will disappear if spin and charge of the black hole becomes very large that it exceeds the limits. The event horizon plays the effectively as a prison, as everything trapped inside it. A repulsive force is created due to spin and objects are pushed away by this force. The gravity of the black hole is surpassed by the spin if the spin crosses the limit and it will dissolve the event horizon. Similarly, the electrostatic repulsion would dissolve the event horizon if charge on black hole becomes too large. The black hole would be unable trap the near by objects without the event horizon and after approaching the singularity, they could escape from it. As in this case event horizon has gone means no trapping gravity is anymore. So, we might consider the blackhole destroyed.
Overfeeding The Black Hole
Over feeding the black hole is a method in which the objects that have a huge amount of charge or angular momentum (spin) overfeeds the black hole to destroy the event horizon. If these objects are thrown into the black hole In Such amount that theoretically a point is reached at which the spin or charge becomes too huge and causes collapsing in event horizon. However, its not easy to tackle the gravity or event horizon by this method practical.
By taking a charged black hole as an example. If more particles, with same charge as on the black hole, are fed up in the black hole then by this over feeding the electrostatic repulsion between the particles and black holes would grow stronger. As no particles added in blackhole is increased, so repulsion becomes the strongest. Because this strong repulsion, no more particles could enter the black hole. Spin also follows the same limit. A black hole refuses to absorb any more angular momentum if it will reach a certain level of rotation.
Whether it’s possible to bypass these limits it is important debate among physicists and astronomers. If we throw the exact amount of matter, as suggested by some theories, just before it reaches its limit. In this way we might be able to overfeed it. This idea remains speculative, but it’s an exciting possibility.
What happened if a black hole is destroyed?
The Problem of Naked Singularities
If a black hole in other words event horizon is destroyed successfully then what will happened as a result of this destruction, a naked singularity would remain behind—an event horizon is not hiding singularity behind itself. As singularity is the point of infinite gravity. So, it presents the problems for physics which could not be ignored because due to infinite gravity, all physics laws are failed due to severe bent of space-time at these points. The singularity exists without effecting rest of the universe because in a black hole with an event horizon, the singularity is safely hidden in the future of anything that crosses the horizon. On the other hand, a naked singularity would be visible and accessible. It would introduce unpredictability into the universe because it represents space-time breakdown. The existence of space-time is ceased at the singularity and meaning of concepts “where” and “when” is lost. Near a naked singularity anything can happen e.g., objects could out of the blue, break down the causality, and the fundamental rules of the universe would become uncertain.
It is believed by the physicists that naked singularity is prevented to form by nature in some way. The chaos brought by the naked singularity, is shielded by the creation of an even horizon. The universe would descend into the unpredictability, without this safeguard provided by the event horizon, where the very fabric of reality does not make sense anymore.
The Safest Method to Destroy the BlackHole
Hawking Radiation
Significant challenges are raised when a black hole is destroyed by using overfeeding it or stripping away its event horizon. There is only one way to destroy black hole is Hawking Radiation. Hawking radiation is a process in which mass of all the black holes is lost slowly, where the tiny particles are emitted by them. As time passes by due to these radiations’ energy is lost by the blackhole and its size is shrieked. Eventually, these black holes are evaporated completely this radiation causes black holes to lose energy and shrink. Eventually, they will evaporate completely. But this process is incredibly slow. If a speck of dust is considered as a black hole, 10⁴⁴ years are required to evaporate this completely. So, an unfathomably long time is required to destroy a black hole by this method. There is no threat to the stability of the universe if black hole is disappeared this natural and inevitable way.
Should We Destroy BlackHoles?
Theoretical, a black hole can be destroyed by eliminating its event horizon or by Hawking radiation for which many million of years are required to evaporate a black hole completely. But significant challenges and risks are associated with these methods of destroying black hole. The event horizon are dissolved due to overcharging or spinning in a black hole, which causes naked singularity. This naked singularity can destabilize the universe and all physically laws are broken down at this point. The safest approach to obliterate a black hole is to decay with their natural course and evaporate over time. As black hole has terrifying reputation, but in actual black holes act as protectors because they provide shield of our universe, from the other neighbouring universes. They are protectors of the universe because hide chaotic nature of singularities safely from view. So, for the stability of the universe, it is not wiser decision to destroy the blackhole. Rather than risking the stability of the universe by destroying the black hole, we should appreciate black holes for the mysteries they hold and the stability they maintain.
Conclusion
Black holes are the bodies with too large gravity in it that any object in the black hole needs escape velocity greater than the speed of light to overcome the gravitational pull of the black hole. It is the most stable entity in the universe. It is also one of the strangest creations in the universe. After death of star, massive core of this star is converted into a black hole. We have various theoretical methods to destroy a black hole but Hawking radiation is the safest among all. When a hole is destroyed, the naked singularity remains behind and cause instability in the universe. So, it not a wise decision to destroy a black hole. We should appreciate the presence of the black hole because they are the protector of the universe.
By
Zeenat Mushtaque, MPhil Solid State Physics
Dr. Abid Hussain Nawaz, Ph.D. & Post Doc
Rumana Gull, Scholar Master of Philosophy Biological Sciences
Excellent effort to explore universe