By: Shifa Malik
Most people have some understanding of what black holes are: an object dense with matter compacted into a tiny space, and a gravitational pull so large that even light can’t resist getting sucked into it, making it invisible to the naked eye. But what about white holes? They are the hypothetical regions around the black holes and there’s no mass around their event horizon, which NASA defines as “the boundary where the velocity needed to escape exceeds the speed of light, the speed limit of the cosmos.” The event horizon is basically the imaginary spherical outer boundary of the black hole and is what prevents us from directly observing a black hole. Not only is the structure of a white hole vastly different from a black one, but the idea of white holes is completely fantastical unlike black holes, and the theories of their existence are very intriguing.
If white holes somehow do exist, it's predicted that they act like the exact opposite of black holes; they blast material out of themselves instead of sucking things in. It’s like if you watched a video of a black hole sucking things in, but reversed. They would somehow not merge with the black hole. Otherwise, these 2 masses would cancel each other out. Another difference is that with black holes, there’s no way to escape them, but in white holes, there’s no way to enter one.
In reality, there’s no proof that white holes exist because no one knows how they are formed. Physicists say that even if one was formed, it wouldn’t exist for a long time because a single atom of hydrogen that crosses its orbit would cause the whole thing to collapse. The reason that black holes have more evidence for their existence is because of the gravitational effect that they have on objects around them. They’re formed by the death of a massive star, once it collapses on itself and leaves a dense core. If the core is a certain size, the force of gravity takes over and creates a black hole. However, the opposite of this process isn’t possible, which is why physicists say that since there’s no possible way white holes can be created, they can’t exist.
However, one event has been hypothesized to lead to the creation of a while hole: the death of a black hole. Carlo Rovelli, a theoretical physicist at the Centre de Physique Théorique in France, wonders what would happen to the matter that a black hole absorbs when they die. He created the theory of quantum loop gravity, an unfinished idea, to try to come up with a line of reasoning for how white holes can be created. However, general relativity equations would have to be ignored for it to work. At the end of the day, it seems scientists just desired to explain the mass that surrounded black holes and put a name to it, hence the idea of white holes.
What’s even more interesting, however, is that a white hole could explain the Big Bang theory: it could explain how a tremendous amount of matter and energy spontaneously appeared. Unfortunately, there’s still a lot to be done in terms of explaining white holes and their existence, but there’s room for new ideas and ways of thinking from the next generations.
What Did You Learn?
1. Can white holes exist?
So far, no theory has been thoroughly backed up by evidence that explains the creation of white holes. However, there are ideas, such as the quantum loop gravity, that could explain the transformation of a black hole to a white hole.
2. What are some differences between white and black holes?
Some differences include what happens with each hole, because white holes spit matter out and black holes absorb matter. Another thing is that white holes can’t be detected but black holes can by their effect on gravity of objects near them.