So, to start off, what is a black hole in your imagination? A cyclone-like, pivoting dark gases that suck in everything passing over into its indefinite pit, or a dark sphere that monumentality dominates its hollow space. Well, the answer is, who knows? Advanced technology is all about probability, processing data and information outputs that drive to potential conclusions. But there is nothing that is considered deterministic until we directly observe it, and a black hole is not an exception. The term is used colloquially to describe an entity where gravity is so strong that it sucks in everything in the vicinity, even light. These objects are not visible to the eye, although they can be detected from its influences and behaviours of light and matter nearby. Frighteningly enigmatic, this dark giant was extremely difficult for even professional physicists to wrap their brain around. It continues to astound scientists the more they study them. Perhaps, the question they have been doubting the most throughout their decades of delving was what happens to matters inside a black hole, whether they are perpetually being stored inside, or destroyed by its extreme gravitational force?
Here is a problem: From the perspective of general relativity, a black hole results if the density of matter becomes too large and gravity collapses the materials all the way to its central point, so-called ‘singularity’. When this happens, gravity is so strong that nothing, even light, can getaway. Unfortunately, an event horizon is the valid point of view for external observers, but not for those infalling, where time freezes at the viewer’s perspective due to gravitational time dilation at the instant. Therefore, we have no information or insights about what life is like inside a black hole, from which scientists had put forward the phrase ‘information paradox’.
Through a series of breakthrough papers, theoretical physicists have come tantalisingly close to resolving the black hole information paradox that has bedevilled them for nearly 50 years. So, come back at the central issue, will matters end their life once falling into the clutch of these monsters? In conformity with general relativity, physical information once pulled inside the event horizon, the ‘point of no return’, will be considered as it was permanently destroyed. On the contrary, the theory of quantum mechanics firmly suggests that information will never be eradicated. These two field theories have never, yet, come together in a conventional manner of looking things as each always brings different perspectives about the universe. General relativity evocatively portrays the smoothness of gravity, whereas quantum mechanics governs the interaction between grainy subatomic particles.
Hawking Radiation
Intriguingly, during a lecture at the KTH Institute of Technology in Sweden, professor Stephen Hawking had successfully described an unprecedented theory for how our existence could escape an extreme beast like a black hole. The theory, which builds onto an idea that has been mulled over for decades, suggests that when something gets sucked into the event horizon, it is not lost forever as we might expect (one point for quantum mechanics). He successfully drew the idea into elegant mathematical equations that got himself famous. The concept describes the only way things can go from the interior to the exterior, which contradicts with the conventional insights about black holes. This does not mean information remains its original form as it falls into a black hole, instead, it is wrecked down into its fundamental particles, like a piece of paper that is burned into ashes. As a result, when this gargantuan beast is no longer being fed on gases, it is expected to shrink and eventually vanish. Once in the esoteric history of astronomy, black hole, who bears a title of invincibility, was adequately proven that can be defeated, thanks to Stephen Hawking. However, Hawking radiation is an incredibly slow process, where the black hole at the centre of the Milky Way would require 1087 years to fully evaporate.
Holographic Universe
Most profoundly, in the mid-90s, American and Dutch physicists Leonard Susskind and Gerard ’t Hooft had shed new light on the information paradox, proposing that when something passes through the black hole boundary, its information encodes as two-dimensional holographic imprints onto a lattice of incredibly small pixels on the event horizon. This means while physical components of an object are entirely obliterated by a black hole encounter, its blueprint lives on (another point for quantum mechanics). To help warp your head around this, think about a stack of documents being incinerated inside a fire pit, its physical components could be burned into ashes, but the information on them remains.
While these two notions are intertwined, Hawking later deduced, as photons are ejected from a black hole, they pick up information that was imprinted on the boundary and carry it back to the universe. Though, he said at the conference: “The information about ingoing particles is returned, but in a chaotic and useless form. This resolves the information paradox. For all practical purposes, the information is lost.” (general relativity finally has the edge)
By harnessing mysterious clues to the understanding of black holes, scientists have transcended the traditional boundary of science, from which they can fathom the history of the entire universe and ultimate theory of reality. This viewpoint has invited a new look to the universe, which we once perceived as having three spatial dimensions, might instead be written on a two-dimensional surface, just like a hologram. This ‘holographic principle’ may has declared our profound illusion about the world or rendered an alternative way of viewing reality.
References:
BEC CREW, 2015. Stephen Hawking Explains How You Could Escape a Black Hole. [Online] Available at: https://www.sciencealert.com/stephen-hawking-explains-how-our-existence-can-escape-a-black-hole [Accessed 16 November 2020].
Bekenstein, J. D., 2007. Information in the Holographic Universe. [Online] Available at: https://www.scientificamerican.com/article/information-in-the-holographic-univ/ [Accessed 16 November 2020].
Maldacena, J., 2011. lack Holes and the Information Paradox in String Theory. [Online] Available at: https://www.ias.edu/ideas/2011/maldacena-black-holes-string-theoryv [Accessed 2020 November 2020].
Musser, G., 2020. The Most Famous Paradox in Physics Nears Its End. [Online] Available at: https://www.quantamagazine.org/the-black-hole-information-paradox-comes-to-an-end-20201029/ [Accessed 16 November 2020].
Nomura, Y., 2020. Have We Solved the Black Hole Information Paradox?. [Online] Available at: https://blogs.scientificamerican.com/observations/have-we-solved-the-black-hole-information-paradox/ [Accessed 16 November 2020].
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