-By Rohan Purohit
Ever wondered what makes the world we live in so interesting, it’s the curiosity to learn new things. Living in a small globe, that is just a tiny dot in the infinite universe. We, humans, try to solve every mystery’s that the universe has to offer. When we watch upon the infinite wonder sky in the night, thoughts start seeding in our mammalian brain about how all things started, how the Milky Way galaxy was formed or how the universe got started or it was the same forever and the most important of all, what is our fate in it. We don’t that if we will ever get answers to this entire question. But one thing is for sure we will always keep asking questions.
Here we are going to ponder upon a super mystical cosmic entity and no it is not a black hole. It’s the opposite of that. Every coin has two sides if there is light there’s dark, if there is sin there’s a virtue. In the same way, white holes are black holes contrary. These beings are the same godly and enormous as black holes only with a fundamental difference. Back holes absorb or suck all the matter whereas a typical white hole throws matter out of itself. Scientist up to now only have postulated about a white hole, never actually found one .but it doesn’t mean that they don’t exist. They are very hard to find due to their build.
According to general relativity, white holes are the hypothetical region of space-time and singularity that cannot be entered from outside, but light, matter, and information can escape vigorously. This makes sense when accorded with a black hole as a black hole can be entered from outside and light and matter cannot escape it. White holes appear in the solution of the eternal black hole concept (eternal black hole concept is a concept where two points far away in space-time connect each other due to a bend in space-time) developed by Einstein. Black holes are predicted to be the past of white holes. It is predicted that each black hole will turn into a white hole in some billion years.
Supermassive black holes are predicted to be theoretically situated in the center of every galaxy and without one SBH no galaxy can be formed or regulated. Stephen hawking’s predicted that these supermassive black holes are the place of origin of the supermassive white holes or big bang.
OUTLINE
Like their older sibling, white holes also have physical properties like mass charge and angular momentum. These cosmic beings also attract matter like any other thing but the object falling into a white hole would never reach its event horizon (discussed in our 3rd article in the black hole series). Though in the case of the maximally extended Schwarzschild solution which is discussed in detail below the white hole’s event horizon in the past becomes a black hole’s event horizon in the future. Acceleration due to gravity (like 9.8 m/s in the earth) is always the greatest on the surface of the body. But a black hole lacks a surface, so the acceleration due to gravity increases exponentially, but never reaches a final value as there is no surface in a singularity.
According to quantum mechanics, a typical black hole is predicted to emit hawking’s radiation so that it can come to the state of thermal equilibrium with a gas of radiation (although this is not compulsory). Because a thermal-equilibrium state is time-reversal-invariant, Stephen Hawking argued that the time-reversal of a black hole in thermal equilibrium results in a white hole in thermal equilibrium (each absorbing and emitting energy to equivalent degrees). This theory put forward by Stephen hawking could mean that black hole and white hole are the same structure. Here the hawking’s radiation from a black hole is identified to be energy and matter that is emitted by the white hole. The semiclassical theory at which this concept sits is also described in quantum mechanics.
ORIGIN
Somewhere around the year 1964, a Russian cosmologist Igor Novikov put forward the existence of white holes. White holes are a part of the solution to Einstein’s field equation also known as described as an eternal black hole with no charge and rotation. Here maximally extended means that the cosmic entity should have no edges and will be allowed to move in a straight line from any trajectory and would keep moving to its future until and unless its trajectory reaches the gravitational singularity like the ones found at the interior of the black hole’s center. To satisfy this theory apart from the black holes interior region, which is its event horizon from which the object will fall, there must also be a white hole’s interior region that would allow extrapolating the trajectories of particles that an outside observer see rising away from the event horizon.
No one has found a white hole till now, but this doesn’t mean that they don’t exist. It is only that they are very hard to detect. Recently some scientists have observed phenomena called the gamma-ray burst. This gamma-ray burst that is formed due to the collision of two neutron stars released energy for 10 seconds is equal to the magnitude of energy that the sun will be releasing up to 10 billion years. Scientists are predicting that there might have been a white hole formed. Einstein Rosen’s Bridge aka the wormhole (the tunnel that connects two distant places in space-time in the same or different universe) also requires a white hole to complete. But if the bridge exists then also it will be impossible to enter and travel through it as that would be very unstable and would collapse in a matter of seconds. There is also another reason because nothing can enter the white holes event horizon and a person falling towards the black hole will inevitably reach the black hole’s singularity.
SUPERMASSIVE WHITE HOLES/BIG BOUNCE /BIG BANG
A Group of theoretical physicists suggests that supermassive white holes may be the key to how the universe started. These theories started coming to play in the 1980s which predict the known universe as a subset of the actual universe created by the supermassive white holes when they released a massive amount of matter in all directions. This theory is popularly known as the big bounce.
According to the theory of general relativity, the gravitational collapse of an object with a compact mass forms a black hole. But according to quantum mechanics, the minimal coupling between two fundamental particles generates a repulsive spin-spin interaction at extremely high densities. So instead of forming a singularity, the resultant formation is an Einstein Rosen bridge. In this case, one side matter collapses and on the other forms a new baby growing universe. For the observers, the parent universe appears as the white hole only. Accordingly, the observable universe is the Einstein–Rosen interior of a black hole existing as one of possibly many inside a larger universe. The Big Bang was a nonsingular Big Bounce at which the observable universe had a finite, minimum scale factor.
But keeping all these things aside the scientist mostly discard this thing because no one knows how a white hole originates. If it originates when a black hole dies then was there a black hole before the universe was created, was there a gravitational singularity that could create a white hole, this question remains unanswered. Stephen Hawking wrote in his book that black holes generally emit energy and radiation known as hawking’s radiation to come to a state of thermal equilibrium and in this process, a black hole slowly disappears. This also contradicts the formation of white holes after black holes.
CLOSURE
After we got to see the actual image of a black hole in our near galaxy our visions about space has changed so much. Now human beings are limitless with only one single goal to solve the mystery of how this all started. Till now the most accepted explanation about the origin of the universe is the big bang theory. But after the arrival of quantum mechanics, we have got a new angle to view things very differently. There is no single solution that can merge the theory of relativity and quantum mechanics. Thus the fate of anything related to the infinite cosmos cannot be predicted with 100 percent surety. But soon we hope to find the essence of our creation.
Video References to watch:
REFERENCES
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https://www.space.com/white-holes.html
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