What Is A White Hole? [White Hole vs Black Hole]

What Is A White Hole? [White Hole vs Black Hole]

We talk and hear a lot about black holes. If you think about it, the whole movie Interstellar, came to life inside that black hole. And that’s something no human has ever even done. We know that Stephen Hawking has been working on some of those theories for a while. And he has thoughts about the movie too.

Look it up if you’re interested in that. But if you’ve been wandering the internet trying to find out about white holes and white hole vs black hole, well, then this is certainly the right place. There are also wormholes to learn about, but we’ll save that for a rainy day.

Ready? Let’s get started…

What Is A White Hole: Short Summary

A white hole is the theoretical twin of a black hole. It is the opposite of a black hole which means if you were watching a video of a white hole it would look like a black hole in reverse.

A white hole is different from a black home in the sense that here, space-time flows in the opposite direction. That means in a black hole, space-time flows towards its event horizon, whereas, in a white hole, it flows away from the event horizon.

Watch: What Are White Holes? | General Relativity

What’s a White Hole? Is it Real?


In layman’s terms, an event horizon is the point of no return. In a black hole, that’s the point from which nothing escapes. Not even light.

As mentioned before and as the name suggests, the white hole is the opposite of a black hole. Physicists describe it as the place where time reversal takes place. Like black holes, they also have mass and rings of gas and dust near their event horizon. This is the boundary between the white hole and the universe.

A white hole is a convention of general relativity because it contains the same equations that cause the existence of black holes. They’d have to for them to be twins, right?

White holes are also supposed to spin just as their twins do. But there are many differences and the biggest might be this. Black holes suck things into their space and those things, including light, never escape. And white holes do the opposite, which means anything that enters their atmosphere can actually escape.

But the most amazing fact about white holes might be that we don’t really know how they form. Black holes are the result of a star that collapses. But we can’t work it out backward to figure out how white holes are formed because that would just result in the formation of a star.

Interestingly, it is postulated that if you were anywhere near a white hole, you wouldn’t be able to tell because they are supposed to look exactly like a black hole. Now, the only difference might be that black holes don’t have a belch and white holes supposedly do.

So, if astronauts are sitting on a stakeout and see something escape a black hole, they are looking at a white hole. And in all the time that we’ve spent in space, we’ve never seen one of those yet.

Could White Holes Ever Be Real?

This is what makes the conversation interesting. It seemed for a while that, just like wormholes which also don’t exist (but might), there is a mathematical possibility for white holes to exist. Wormholes are described as contortions in space-time that are possible mathematically but probably not in reality.

Einstein and Nathan Rosen discovered a wormhole solution in 1935. That’s also why wormholes are sometimes referred to as Einstein-Rosen bridges. If you’re a Thor fan, you know it as the Bifrost. They are little connections in the time-space continuum that are shortcuts in space-time.

Since the 1970s, we’ve had this theory that over time, a black hole could shrivel and die since it leaks energy. That it leaks energy was the discovery made by Stephen Hawking.

But we’re still not sure that if a black hole does shrink and die, what happens to all the things that a black hole swallowed over its lifespan? According to quantum mechanics, the information can’t be deleted and according to general relativity, it won’t be released.

We also don’t know how a black hole might die just as we know nothing about how a white hole might form. There are also a lot of equations in the general relativity theory that forbid us from imagining that the death of the black hole is the point of birth of a white hole.

Now, according to Carlo Rovelli, who proposed the quantum loop gravity, there might be a scenario when a black hole shrinks to a point where it doesn’t obey any of the laws of general relativity. This is something that all billiard balls and stars follow.

Rovelli’s quantum loop gravity is incomplete, but it suggests that space is made of particles like Legos. It was his attempt to go beyond general relativity to find answers.

Rovelli and some others were the ones to theorize that at some point, the black hole doesn’t obey the laws it should and hence, the particles participate in quantum randomness. This phenomenon dominates the black hole, which has now shrunk, and it results in the formation of a white hole.

It’s a tiny little white hole whose mass is the same as one human hair. That’s barely anything and it also doesn’t have any of the monstrous gravitational pull that black holes do.

However, it would have an interior that preserves all the information that once existed inside the black hole. That seems to explain some of it, does it not?

Now, this white hole is also too small to attract any matter that might be orbiting around it. But it might just be stable enough to tell us about all the things that got sucked into the black hole that existed before it.

If any of this becomes true, white holes would be a dominant force in a universe where all black holes have shrunk and stars have burnt themselves out. It would be very easy to see these particles because they would grow to be huge. But we’re probably not going to get there anytime soon.

Black Holes: A Space Where Singularity Exists


In 1915, Einstein presented field equations that blew the whole scientific community away. As a matter of fact, theoretical physicists are still trying to make sense of some of them. Not only did he describe gravity, but he also proposed theories that taught us a lot about our reality.

His idea was that the mass of planets and stars could fold and bend time and space. This got everything thinking and calculating how much “abuse” a given space can take from the matter that is moving aimlessly out there.

It didn’t take long to figure some of these things out because an astronomer and physicist called Karl Schwarzschild solved one of Einstein’s equations. He figured out how space-time changes when it encounters one ball of mass.

This was the beginning of understanding what we now called a singularity.

It’s a word that’s thrown around quite a bit and the simple explanation is this. It’s a mass that is spherical in shape and is shrunk to a point that is infinitely dense. The space around this mass is wrapped so tightly that it is completely removed from the rest of the universe.

It’s the space equivalent of a no man’s land where the event horizon no longer links cause and effect. The most popular example of a singularity is the black hole. They have an event horizon from where nothing comes out because there is no exit.

Things outside the black hole can have an impact on the horizon, but it doesn’t work the other way around.

Now, in the 1960s, a mathematician called Martin David Kruskal continued developing the definition of a black hole. Somewhere in that process, he inadvertently described the existence of the black hole singularity. He just didn’t realize that he was providing the very first glimpses of a white hole.

Isn’t that quite something?

Frequently Asked Questions

Q: What Happens If We Fall into a White Hole?

A: Just like in black holes, there’s no event horizon in white holes either. So, they will attract matter, but it never gets anywhere since there’s no surface, so to speak.

Q: What Would Happen If a Black Hole Hit a White Hole?

A: In a hypothetical universe where this might happen, the white hole will turn into a black hole. But they won’t merge after the collision. As a result, we will have two black holes.

Conclusion & Summary

White holes are theoretical in their existence. They are supposed to be the exact opposite of a black hole. Space-time flows in the opposite direction in a white hole when compared to a black hole.

That means while everything at a certain proximity to a black hole gets sucked in and lost forever, things could escape the pull of a white hole. That’s because in all likelihood, it’s not a pull at all.

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