What Are White Holes? Do the Black Holes’ Neglected Twins Really Exist?

Black holes have captured much of the scientific community's attention due to their intriguing nature. Many studies have been conducted on this cosmic body, and the first image of a supermassive black hole at the center of the Milky Way galaxy has been unveiled. Recently, astronomers expressed their interest in encountering the black holes' mirror twins known as white holes.

What are White Holes?

To understand white holes, we must first examine the nature of the more familiar black holes. Black holes refer to a region in space described by complete gravitational collapse. In this area,e gravity has overcome all the other forces in the universe and compressed a body to an infinitely small point known as a singularity. The singularity is surrounded by an event horizon, a border with a strong gravitational attraction that not even light can escape.

When a massive star dies, its immense mass collapses onto its core, triggering a black hole. Any form of matter or radiation that gets too close to the black hole can get trapped by the strong gravity and dragged beneath the event horizon.

To arrive at the concept of a white hole, we must return to the Theory of General Relativity. Since general relativity is not affected by the flow of time, the mathematical equations can be applied perfectly by running forward or backward in time.

If we watch the formation of a black hole and run it in reverse, we will arrive at an object that streams radiation and particles. It will eventually explode and will leave behind a massive star. This white hole was formed in a perfectly fine scenario according to general relativity.

White holes are assumed to be stranger than black holes. Like their twins, they also have singularities at the center and event horizon at the borders. They are also expected to be massive bodies that gravitate to objects. However, any material that enters a white hole could get ejected immediately faster than light, causing the white hole to shine. Anything on the outside of a white hole cannot get inside it because it needs to travel faster than the speed of light to cross inward through the event horizon.

Can White Holes Exist in the Universe?

Although white holes are mathematically allowed by general relativity, astronomers cannot easily suspect that they exist in the real universe. This is because the inner workings of the universe can also be affected by other branches of physics, such as the theory of thermodynamics, which describes the concept of entropy.

Entropy refers to a measure of the disorder in a system, focusing on the distribution of energy and mass. According to the second law of thermodynamics, the state of entropy of closed systems will always go up. In short, the disorderliness of the entire universe always increases.

The formation of a black hole cannot be run in reverse to create a white hole because it will decrease the entropy of the system. In short, stars cannot just miraculously appear out of enormous cosmic explosions. So, although general relativity supports the reality of white holes, thermodynamics saysit is impossiblee.