If black holes are the entry hole into the complete unknown, then could there be an exit hole?
White holes are the opposite of black holes, it is one of the astronomical issues that the search for is still ongoing, and one of the things that drives scientists to search for white holes is that question that I asked at the beginning, when black holes swallow those planets, galaxies, and stars, you see where they go The stuff from those planets, where does it go when it's swallowed?
The expression white hole is a metaphorical expression, so it wasn't called by this name because its color is white, but only because it is considered the anti-hole of the black hole, so it was called the white hole.
When you reach the point of no return within the limits of the black hole, which is called the event horizon, and it is the region that if you reach in the black hole, you will never be able to return, and it is just like reaching the edge of the waterfall where no rowing or anything works, so your fall is inevitable.
Accordingly, suppose that an apple will fall into the abyss known as the singularity, and it will be lost inside the black hole, but will the apple be lost?
Or will it come out from somewhere else in the form of another substance?
Theoretical physicists always think about these strange assumptions, as I always tell you, man is a curious being by nature and wants to know everything.
In 2006, a gamma-ray emission was observed in space, but this emission was very strange, as it had a relatively long duration of 102 seconds, meaning that this time is even longer than the time of the "Supernova" explosions.
And at that time when gamma rays were emitted, they noticed that the strangest thing of all is that there is no explosion for any star. Here, scientists asked, as long as no star exploded, where did these rays come from?
It has been suggested that this event may have been a white hole that came into existence, ejected some matter from its core, and then collapsed in on itself in a huge explosion.
Although this explanation seems unattainable, it prompted astronomers to think again. The scientifically impossible is theoretically possible. Well, what if someone approached the white hole? what would happen?
Imagine with me that you are in a space car and heading towards a white hole, you will collide with a terrible amount of energy emitted that will collide with you face to face as it is coming from the white hole and your space car will be destroyed even if this car is not affected by gamma rays, or is not affected by the emission of energy, the distortion of space-time Around white holes will make the mission impossible.
And the required acceleration of your vehicle will become greater and greater, while your poor car will go slowly and slowly. No energy in the universe can get you into the white hole. Of course, this remains an assumption from some scientists.
White holes also have an event horizon, which is the region of no return, but what is distinctive about this horizon is that it is the opposite of a black hole, no one can enter it, while in a black hole, no one can get out of it, because the event horizon of the white hole exists in the past and anybody that will exit from it will increase its energy relatively.
When our apple reaches the black hole's event horizon, the region of no return will become the present and future of that apple inside the black hole, and we have no hope of seeing that apple again.
If we could observe the apple falling into the black hole, it would take an infinite time to fall, but this is what we will see. As for the apple, its fall will be very fast, without affecting the time at that point to the apple itself.
The concept of a white hole also appears in explaining the concept of a wormhole. A wormhole consists of a black hole located on one side, suppose it is on the right, and it pulls anything into it and swallows it, and the white hole is supposed to be on the other side, and it removes matter from it.
It almost seems like this, according to scientists' understanding, and the wormhole is unstable, as it is erased from existence when it interacts with matter, and its existence was assumed only as a solution to Einstein's equation.
The white hole is defined by scientists as the theoretical opposite of the black hole, as you can enter the black hole from the outside, while you can never enter the white hole from the outside.
Likewise, the black hole is the place where the matter that enters it disappears, while new materials appear in the universe starting from the white holes, such as a woman giving birth to a new baby, almost the same idea, the main difference between them, is the activity of the event horizon, one of which is withdrawing and the other is exiting.
Each galaxy contains a super-massive black hole in its center, in addition to other small black holes scattered here and there in galaxies, but as for white holes, they exist in theory only, and scientists haven't yet been able to monitor not one of these white holes.
The biggest problem is thinking about how these white holes arise, as the black hole is formed as a result of the collapse of a great star with the effect of its gravity, after it exhausts all its fuel, at that moment the star collapses to form a very dense point called the black hole.
It swallows anything so that light cannot escape from it, but for a white hole to exist, one needs something similar to a great gravitational explosion, and the puzzling thing about this whole thing is how does that happen?
No one to this day knows how white holes are born, white holes are still to this day only hypotheses and guesses that there could be a white hole, but not a single white hole has been observed and monitored to this day, and there is no evidence, even if evidence relatively weak to exist.
Therefore, white holes are considered something that fascinates the imagination of scientists, and despite this, the search for them is still ongoing.
But who knows, in this vast universe anything is possible.