What is on the other side of a black hole?

This article was written by Sanaa Suvarna, a 17-year-old student from India who won third place for her outstanding article on the topic of “What is on the other side of a black hole?”. Sanaa effectively embodied her insightful research and creativity into addressing this paradox. Well done to Sanaa!

In March of 2020, streaming giant Netflix released the documentary film “Black Holes: The Edge of All We Know”, attempting to decipher the ever-mysterious black holes. While it primarily focuses on capturing the first-ever image of a black hole, it also speculates whether the information that goes into a black hole is truly lost— a question whose answer seems to be eluding the grasp of puzzled physicists. It is theorized that the information isn’t completely lost but rather reconstructed before being returned. However, there is still a large fraction of information that gets absorbed and is seemingly ‘lost’— a direct violation of quantum theory. As a result, it is only plausible for there to be something at the other side of a black hole that allows the ‘lost’ material to still exist. There are three possibilities for what could lie on the other side of a black hole: an exit point, or a white hole, which ejects all the absorbed information; an exit point to a specific time period; or a destination at another point in the universe.

The existence of a white hole is feasible because information becoming lost contradicts quantum theory. The concept of a white hole was introduced by Russian cosmologist Igor Novikov in 1964. He hypothesised that a white hole would be the exact opposite of a black hole— information cannot enter, but it can be ejected. Picture someone puncturing a water balloon: the surface of the balloon curving slightly before exploding, water splashing everywhere. Play this in reverse and you have a fair idea of what the formation of a white hole would look like— a phenomenon some physicists believe is mathematically impossible to occur. But one must remember that information simply cannot be lost. The idea of a white hole might seem impossible and absurd currently, but remember, space travel was first considered ridiculous and the very idea of sending an object into orbit was laughable.

The prospect of time travel is one that excites many. This prospect, however, can become reality because of black holes. It is widely known that a black hole has a tremendous gravitational pull that not even light can escape— despite the contrary being portrayed in the popular film “Interstellar” with planets thriving dangerously close to large black holes. As a result, a black hole acts as a natural time machine since these colossal gravitational forces are capable of slowing down time more than anything else in the universe. A spaceship equipped with the appropriate technology would be capable of using this phenomenon like a surfer takes advantage of a rising wave. On earth, one orbit of a black hole takes approximately 16 minutes which translates to approximately 8 minutes at the horizon of a black hole. Convert this to years and we conclude that a spaceship crew circling a black hole for roughly 20 years on earth is only spending 10 years of their lives moving in a circle. If they returned to earth, they’d be ten years younger than their peers. Expanding upon this, it might be possible that entering a black hole could slow down the process of aging even more, provided we have technology that can withstand the gravitational forces and remain intact throughout its journey. But is it truly possible to harness these colossal curiosities? As Barbie is known for saying, “Anything is possible!”— so who’s to say that with the proper equipment and technology, it isn’t possible for us to experience time travel. Many technological advancements today were akin to sorcery at their conception, but ask a passerby about traveling in a plane today and they’d say it’s as easy as taking a stroll in the park.

Lastly, it is plausible that a black hole acts as a bridge between two different points in different galaxies. This theory— known as the wormhole theory— proposes that a black hole could allow us to pass through it and enter another point in the universe. This idea was conceptualised by Albert Einstein and Nathan Rosen, who built upon the original idea of an Austrian physicist Ludwig Flamm. In short, two black holes would act as entrance or exit points with a ‘tunnel’ stretching between them that allows travelers to reach their destination in a shorter time period. Much of this is based on theory, leading to the development of theoretical problems. For example, wormholes are susceptible to collapsing quickly because of instability. This theoretical problem could be fixed by allowing “exotic matter” to pass through in order to stabilise a wormhole. However, wormholes haven’t been discovered yet and speculation can only lead us so far. Until we have tangible proof of wormholes being impossible to travel through, there’s no reason to simply give up on this potentially important idea.

The existence of white holes, time travel and wormholes might seem like science-fiction currently, but could become reality in the future with an abundance of research and exploration— and what is science if not the process of researching, making errors and exploring? As Jules Verne said, “Science, my lad, is made up of mistakes, but they are mistakes which it is useful to make, because they lead little by little to the truth.”—unless we continue trying to decipher the ever-so-curious black holes, the plethora of knowledge they contain would forever remain hidden.

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Featured image retrieved from: https://www.space.com/where-do-black-holes-lead.html