Our universe is filled with mysteries. Throughout the history, science has been trying to solve the enigmas that surround us. Science has been able to find solutions to these enigmas at least on the earth where man lives. But, the study of space and time has made scientists to doubt their skills and previously established facts and laws by them.Since the beginning of scientific knowledge, man has looked to the stars with awe.
Amongst then and now, many advances have been made in the fields of space science, arithmetic, and material science trying to clarify the things we see above. Yet the more we try to comprehend and understand about outer space, the less we truly appear to know. In something as large as the universe, there will undoubtedly be unexplainable marvels and conundrums for which we really cannot find a solution to or at least it seems so. Even a particle, small as an atom, has caused scientists to come up with new laws of Quantum mechanics. Quantum mechanics is the science of the very small. It clarifies the conduct of atoms and subatomic particles with energy. Newton was successful in laying down foundations of classical physics which explained how gravity and time worked in a non-inertial frame of reference i.e. our earth.
Einstein explained how science worked in space and thus laid down the laws of modern physics the most prominent of which being the Relativity theory. Einstein’s ideas contributed much to our knowledge of the space sciences and gave a new direction for scientific research till we came across the most mysterious objects that are part of our universe “The Black Holes.” A black hole is an area of space-time displaying such strong gravitational force that nothing, not even light can escape from inside it. The hypothesis of general relativity predicts that an adequately minimized or compact mass can turn space-time into the black hole. Since no light can get away, dark holes are imperceptible. But special space telescopes can detect dark holes. They can watch the conduct of material and stars that are near dark holes. The edge of a black hole is termed as “Event Horizon”, after crossing which any object, even light, gets disappeared. A geologist, John Mitchell, was the first person to give the idea about black holes in the eighteenth century. According to his calculations, that if the Sun can be compressed down to a great extent, then it would have so much gravity that in order escape it, one will have to go faster than the speed of light.
At first, black holes were considered hypothetical; but Einstein really believed in them. (Begelman, 1898-1899). However, in 1931, the space expert Chandrasekhar claimed that specific high-mass stars may have the capacity to collapse into black holes.( Brügmann, 10526). (Israel, 357). The claim turned out to be true as decades later astronomer’s found many black holes in outer space. Black holes are formed when a star dies. That is to say that when a star reaches the end of its cycle, it undergoes an explosion called “supernova”. If the star has mass 3-4 times the mass of our sun, it collapses due to its own inward gravity while there is no outward gravity to keep the star stable. As there is no outer gravity, the star keeps on shrinking until it becomes the small but highly dense center with strong gravitational pull. (Klein). ( Overbye). Although much of the facts about black holes have been discovered, yet the one that is even today a great deal of confusion, is the fact that if everything that goes into the black holes is lost, then where does it go? More importantly, whether or not the information about the objects remains preserved? This has led to the formation of the infamous conundrum of the modern times “The Black Hole Information Paradox.” To arrive at why this paradox exists, we need to know where it comes from. This paradox is a result of the mix of quantum mechanics and general relativity. Scientific calculations show that physical data can disappear into a black hole, allowing all physical states to deteriorate into a similar state. This is questionable on the grounds that it disregards a generally accepted fact of science—that fundamentally, data about a physical system at one point in time should decide its state at some other time.
According to Quantum mechanics, information about every physical existence should remain preserved no matter what. Quantum mechanics treats information like energy. Energy can neither be created nor destroyed but it can be transformed from one state to another. Hence when an object falling into the black hole crosses the event horizon, it freezes. That is to say that one of the postulates of Relativity is theory is time dilation; when the object enters the boundary of a black hole, time dilates. And so it appears that the object has stopped moving thus preserving the information. Such hypothesis abides by the rules of quantum mechanics and general relativity. But, the problem arose when Stephen Hawking predicted that like everything else, black holes have some certain temperature and they would vanish away until there was nothing, discharging their mass and energy back into the Universe. Such radiations emitted by the black holes are called “Hawking Radiations.” And, this is where the information paradox appears. The information within the black hole is conserved due to time dilation but when a black hole evaporates, releasing all the energy in form of Hawking radiation, what becomes of the information that is supposed to be preserved in order to satisfy the principles of quantum mechanics?( Matsubara, 2-3). Such conundrum is known as “black hole information paradox.” This paradox originated in 1974-75 when the concept of black holes radiating “Hawking Radiations” came out. It is an established fact that information paradox exists and scientists are constantly trying to come up with new theories to resolve this paradox. These include hints of the existence of white holes, suggestions that the object leaves a blueprint on the two-dimensional hologram around the event horizon, and suggesting that an object ends up in the parallel universe.
One of the theories to solve the information paradox is the existence of white holes. White holes, as the name suggests, are the opposite of black holes. A white hole is a hypothetical object in the universe. The white holes do not allow anything to enter them. This behavior is contrary to that of the black hole which forbids anything from escaping it. The idea of white holes came into being when astrophysicists investigated the region around a black hole and imagined that there’s no mass inside. In a similar theory, it is predicted that a black hole singularity would compress down to the smallest size. At that point, it would bounce back as a white hole. That is to say that when a black hole dies, as predicted by Stephen Hawking, it might get transformed into a white hole ejecting out everything that it ever swallowed.
According to physicists, there comes a time when black hole stops shrinking into dense center known as a singularity. They believe at some point, the quantum mechanics rules come into action and counter the process of gravity reaching infinities. The Physicist, Carlo Rovelli of Aix-Marseille University in France, has pointed out that it is actually space time that is quantized rather than the gravity itself. Space time is made from tiny, singular loops that cannot be divided anymore (Cain). (Cowen). Of course, the loops in this ‘loop quantum gravity’ are a hypothetical endeavor and has yet to be supported by scientific laws. (Cowen). ( Peterson, 376-377) These loops would be so tiny that space-time would look normal to an observer. Hence a point would be reached within the black hole where it would not be able to shrink anymore. It would then exert outer force known as “quantum bounce” and it would turn into the white hole. This entire process abides by the rules laid down by Einstein. This can provide an answer to one of the enigmas related to black holes i.e. “information paradox.” This theory provides a plausible key to figuring out how the information remains preserved if the black hole dies. (Narlikar, Apparao, 590-591 .).
Physicists have discovered that the effect of formation of white holes includes quantum impacts that are very impracticable. It is seen that the quantum bounce can infringe the most important criteria of physics i.e. the entropy which is the measure of the disorder of a system. (Cowen). If a quantum bounce takes place, the entropy of the system would decrease but a system’s entropy can only increase and never decrease. This is a paradox itself. The authors of this theory Rovelli and Haggard, assert that entropy would not decrease although they do accept that their paper still needs to be furnished in terms of calculations. (Cowen). The existence of white holes is still questionable as science has not been able to locate them. However, they have discovered changes in energy in the universe that demands the existence of white holes. It is hinted that astronomers may have discovered first white hole back in 2006. A gamma beam burst in 2006 did not fit with scientist’s knowledge of where it came from. The beams’ duration of 102 seconds implied that it must have originated in a supernova blast, but then there were no supernovas there for it to have originated from. It was a mystery for scientists and five years later i.e. in 2011, it was suggested that the gamma ray must have come from the white hole.
This also led to the idea that white holes are extremely unstable and as soon as they are formed, they collapse within themselves, bringing about a huge blast. And these blasts are responsible for energy imbalances in our universe. (Cowen). Despite the fact that such explanation does not clarify things a lot- still, it is something for scientists to hold onto to explain information paradox. However, they have discovered changes in energy in the universe that demands the existence of white holes. It is hinted that astronomers may have discovered first white hole back in 2006. A gamma beam burst in 2006 did not fit with scientist’s knowledge of where it came from. The beams’ duration of 102 seconds implied that it must have originated in a supernova blast, but then there were no supernovas there for it to have originated from. It was a mystery for scientists and five years later i.e. in 2011, it was suggested that the gamma ray must have come from the white hole. This also led to the idea that white holes are extremely unstable and as soon as they are formed, they collapse within themselves, bringing about a huge blast. And these blasts are responsible for energy imbalances in our universe. (Cowen). Despite the fact that such explanation does not clarify things a lot- still, it is something for scientists to hold onto to explain information paradox.
One explanation to black hole information paradox is the belief that black holes are actually portals to a parallel universe. The information might not be frozen in the exterior radius of the black hole as previous studies have shown but it might end up in the interior of the black hole. The legendary Physicist, Stephen Hawking extended his work on the black holes and came up with the idea that the information within the black hole is not lost forever but ends up in another universe. This way the quantum theory about the preservation of information remains correct. Hawking also suggested that once the information ends up in the parallel universe, it cannot come back. ( Overbye). (“Stephen Hawking: ‘If you feel you are in a black hole, don’t give up. There’s a way out”). (“No Escape From Black Holes? Stephen Hawking Points to a Possible Exit.”). Some astronomers have discovered that for black holes to be a passage to another universe, they would first need to be converted into wormholes. Wormholes are actually texture of space-time that connects one universe to another.
Scientists were surprised to find out that the black holes and wormholes are so similar in structure and behavior that it is very difficult to tell them apart. Sergey Solodukhin of International University Bremen in Germany has claimed that wormholes do not have the event horizon. Things can move in and out of wormholes easily. In other words, wormholes are black holes with just its interior i.e. the singularity. (Shiga). Some astronomers have discovered that for black holes to be a passage to another universe, they would first need to be converted into wormholes. Wormholes are actually texture of space-time that connects one universe to another. Scientists were surprised to find out that the black holes and wormholes are so similar in structure and behavior that it is very difficult to tell them apart. Sergey Solodukhin of International University Bremen in Germany has claimed that wormholes do not have the event horizon. Things can move in and out of wormholes easily. In other words, wormholes are black holes with just its interior i.e. the singularity. (Shiga).
Science hasn’t so far investigated the boundaries of black holes except by telescopes. There is no going around the black hole without getting sucked into it. So it can’t really be said that the black hole might actually be a wormhole. Also, wormholes exhibit no hawking radiation nor do they have any event horizon. This accounts wormholes of whether actually being portals to a parallel universe. They can just be opening and closing to the same universe and not another one. Also assuming that wormholes only consist of singularity, the force of gravity can be so much that it will tear apart anything that goes into it. (Shiga).
Looking at it from this perspective makes it look like information is bound to be destroyed either via hawking radiations, in which info is an indestructible form or by passing through a singularity. According to Stephen Hawking, “this changes everything that we have studied about science. If the information is indeed lost then our histories would become illusionary.” But then again if quantum theory isn’t satisfied by the emission of Hawking radiations, then information been gone to another dimension seems like a satisfactory explanation. (Languipo). According to another theory, scientists believe that singularity does not exist. When something falls into the black hole, it would be like contraction at first but then a sudden expansion. This theory is plausible as it helps to avoid any more confusion.
The most popular solution provided to the information paradox is the one given by Stephen Hawking and his few colleagues recently. Hawking has predicted the existence of “hairs” on the event horizon. This hair forms a two-dimensional imprint of the ongoing information. Hence the information remains preserved abiding by the rules of quantum mechanics. “Hairs” are metaphors for the unique properties of black holes which help to differentiate between them. Hawking’s has stated that whenever information goes into a black hole, it leaves a mark on a black hole giving it “Hairs” which distinguish it from other black holes. Hawking’s had been a strong advocate for this particular theory. Another scientist, Strominger has proposed a similar idea which is that when information gets sucked into a black hole, it adds a “soft photon” to the black hole which forms the “Hairs” on the event horizon. In this way, although the physical matter is destroyed, information lives on forever. (Moskowitz). Hawking said in August, “The information about ongoing particles is returned, but in a chaotic and useless form,” This resolves the information paradox. For all practical purposes, the information is lost.” (Hawking, 1-3).
Hawking seems very well convinced that his idea is reasonable and he might be able to prove it in near future. Still, on the other hand, many scientists claim that his theory has just added to the confusion instead of solving the riddle. Scientists are still questioning as to how the presence of soft hair fully explain the information paradox and it has definitely raised several other questions regarding entropy and state of a black hole. Many scientists are also skeptical about the Hawking radiations carrying the blueprint of information history because there should be a way to decrypt the radiation to retrieve information. (Moskowitz). ( Castelvecchi) . Proposal of the presence of soft hair is just a step forward by Stephen Hawking and his fellow scientists in resolving the information paradox which was also raised by Hawking himself. Despite the fact that the research paper has stirred in controversy, the scientists are optimistic that there definitely is more to come on soft hair which would unravel more underlying mysteries regarding the information paradox. Future holds a better understanding of quantum gravity and understanding the physics of a black hole. (Moskowitz). ( Castelvecchi).
Black holes have fascinated the scientists and astrologers alike for the past 4 decades. Solving the information paradox related to black holes will not only enable scientists to dig deeper into mysteries of the universe but also a step closer to the reality of the physical world. This paradox resolution will also give insights of the creation of this universe i.e. the big bang theory. Information loss paradox is crucial as it quantifies the applicability of quantum mechanics and compares it with the concepts of relativity. This gives us a break to classify the known and unknown implications of quantum gravity.( Renteln, 516-518). According to scientific calculations, physical data can vanish into a black hole, permitting numerous physical states to decline into a similar state.
Although much of the facts about black holes have been discovered, yet the one that is even today a great deal of confusion, is the fact that if everything that goes into the black holes is lost, then where does it go? More importantly, whether or not the information about the objects remains preserved? A white hole is a hypothetical object in the universe whose existence can justify the black hole information paradox. As black holes do not let anything escape from their surface, white holes eject matter and energy and nothing can get inside them. The legendary Physicist, Stephen Hawking extended his work on the black holes and came up with the idea that the information within the black hole is not lost forever but ends up in another universe. This way the quantum theory about the preservation of information remains correct. Hawking also suggested that once the information ends up in the parallel universe, it cannot come back. And according to the latest theory, information is halo graphically imprinted over the event horizon.
All of these explanations do solve the paradox in one way or another. However the solution turns out, it may not help us look deeper into just black holes but also the big bang which is a theoretically related event. All of the theories eventually relate to the origin of the universe. If scientists can find the solution to information paradox, that might be one step closer to knowing the origin of our universe.
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Feature Image Credits: National Geographic