There is a Yin for a Yang, night for day, celery for chocolate, etc. What we are getting at is, in this universe that we live in, there are always the opposite for almost everything. So when you read about black holes, do you ever think about the opposite of it, the white hole? This article will explain what is a white hole if there exists one.
Before we get into this article, let us make this clear that we won’t be focusing on the mathematical aspect of white or black holes. This is important because the majority of the knowledge about black holes and all the knowledge of white holes is from maths. We got to see the first-ever image of a black hole in 2019 and perhaps we’ll never see a white hole. But we can talk about them.
What’s a white hole and why white?
There’s nothing to do with the color of these structures when it comes to naming. Black holes are called so because light cannot escape from it, making it look black. White holes are called so because they tend to emit matter and light and they are t completely the opposite of a black hole. To imagine a white hole, imagine a black hole in reverse time.
Before we elaborate on white h0les, a little bit about black holes. Black holes are created when massive stars die. The mass of the star collapses into a very small space, increasing the gravity so much that a singularity is created. What is a singularity? This needs an article of its own. For now, it is something where the laws of our universe do not apply.
In a black hole, there are some rules. First, nothing that gets inside a black hole can get out of it. The escape velocity of the black hole is more than the speed of light and nothing can travel faster than light. There is a boundary (theoretical) around the singularity called the Event Horizon which is the point of no return. Once crossed, nothing can come out of it. You can read a detailed article about Event Horizon here.
So a black hole is something where things (matter and light) get inside but never come out of it. White holes being the opposite means that nothing can go inside it, but only come out of it. One look at this sentence and anyone with little knowledge of science would say “that’s impossible”. And yes, from what we know, it is.
White holes are completely hypothetical structures that were first introduced in 1964 by the Russian cosmonaut Igor Novikov. The ideas were taken from the solutions of Einstein’s Field Equations. Since the whole idea of white holes is hypothetical, let’s go nuts with this article and explore all the ideas about white holes. I’m just gonna go full science fiction writer here.
Why the white hole should exist?
First, the maths that explains black holes work very well with white holes. Essentially, white holes are black holes in reverse. Another reason for the existence of these structures is everything in our universe has an equal and opposite particle, although in very scarce quantities. Proton has antiproton, the electron has positron, the matter has anti-matter, etc. So if a black hole is taking things in, there must be an outlet for it as well.
There was a scientist called Albert Einstein who came up with the revolutionary theory of relativity. In the field equations for general relativity, the possibility of black holes was also found, first by Schwarzschild. But black holes were theoretical at that time, until 2019 when the first picture of a black hole was taken. But there was more to those equations.
It was observed that the same equations could be solved in another way. An oversimplification of this would be the square root of some numbers such as 16. 4 is the square root of 16, but there is another. -4 can also be the square root of 16. So both 4 and -4, although different reach the same result. This gave the idea of a white hole or the mirror twin of a black hole.
A very widespread misconception regarding white holes is how it behaves around matter. Since white holes are considered to be the opposite of black holes, it is assumed that unlike sucking in matter and light, white holes repel it. So just like two magnets with their same poles repel, a white hole would repel matter. This is not true at all. White holes will attract matter. It is the event horizon where things change.
In a black hole, once you enter the event horizon, there is no returning. You cannot come back into the universe from inside the black hole. In a white hole, you’ll be attracted to the event horizon but never be able to cross it. You can never cross the event horizon. This is how the white hole is different from its black counterpart.
If white holes weren’t improbable and fictional enough, it gets wilder. One may think, how the possibility of white holes explains our existence? Maybe, just like black holes suck in matter from our universe, the same matter perhaps is spilled out to another parallel universe where only white holes exist? Perhaps these boundaries that restrict matter to enter or leave these “holes” are nature’s way of preventing matter from these universes (one with regular matter and one with anti-matter) from colliding?
The reason why I think it is plausible is that white holes operate in reverse entropy which means that instead of increasing chaos, in white holes, entropy decreases. Entropy needs a separate article but we can give a very basic explanation. Entropy means that everything in this universe gets more disordered and never ordered without the input of energy. This means that smoke will always mix with air and never the reverse. This is not the case for white holes.
Since white holes operate in reverse entropy, this means that time runs backward. This is not possible at all. At least not in our universe. But perhaps like our universe with normal matter, there is another universe with anti-matter, reverse entropy, reverse time, and full of white holes? And these whole networks of black holes and white holes could be the connecting veins of these universes, balancing each other with their opposite nature.
Why white holes don’t exist
Coming out of the fantasy land, the probability of having a white hole in our universe is close to none. Yes, we know that there was a time when black holes were also considered hypothetical figments of imagination. But the difference was black holes never violated the integral laws of the universe. White holes violate that. Time cannot run in reverse, not at least in my universe!
Also, if one sees the Penrose diagrams (another article for the), some absurdities are found. Here’s a pill version of the entire mountain; In infinite time, a white hole turns into a back hole. And as established earlier, one can reach near the event horizon of the white hole but never cross it. It would take an infinite time to reach the event horizon but by then, the white hole would become a black hole.
Scientists have also tried looking for white holes in the most distant part of the universe and yet, there has been no observation or any supporting evidence for these structures. It would be safe to assume that there are no white holes or they don’t exist the way we think they do.
It could be plausible that white holes exist at the center of black holes, in the singularity. It is also possible that some white holes existed at the beginning of the universe but now have collapsed into black holes. Although very rare, black holes can also “switch” into white holes for an infinitesimally period of time, so small that it is impossible to detect.
Whatever it is, white holes will be a matter of science fiction for a long time and with the impossibility of their existence, hardly any scientist is enthusiastic to look for these structures. But there is one thing for certain; the discovery of white holes in this universe of any other will be one of the most powerful and revealing events in our species’ timeline. White holes will answer a lot about our universe, our origin, our place in this universe, and finally, our fate. So as long as we are looking for the origin of this universe, we are looking for white holes as well. This concludes the article.
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