Short Wave - Could Wormholes Exist?

Episode Date: May 19, 2025

In science fiction, wormholes are hyperspace subway tubes linking one part of a galaxy directly to another, distant point. But could they actually exist? To find out, we talk to theoretical physicist Ron Gamble, who says wormholes aren't just a matter of science fiction — and they have big implications about the shape of space itself.Want to hear about more hypotheticals physicists have to confront in their work? Email us at [e-mail] — we might turn your idea into a whole episode!Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Space. I love it. And the things inside of it. Us, of course, stars and galaxies I studied. And I even love the other cool hypothetical stuff that mostly lives in science fiction, like wormholes. Wormholes are a funky but possible solution to Albert Einstein's famous equations for the theory of general relativity. These theoretical cosmic portals can shorten a trip for. from hundreds of light years to minutes. Wormholes have been a mainstay of transportation in movies like Interstellar. That's it. That's the wormhole.

And TV shows like my favorite, Star Trek. The aliens who live in the wormhole, as you call them. Which Ron Gamble says is not far off from how scientists think about these wormholes. It's very much like a bridge. You can do this thought experiment yourself. You take a sheet of paper. You fold it kind of like in half and you poke a pencil hole right through the middle. and that is essentially a wormhole.

It connects two points in space and time together. Ron's a theoretical physicist, and he wrote his PhD on funky solutions to Einstein's equations for general relativity, like wormholes. Basically, he did this by studying space time, the four-dimensional existence we all live in. It includes three dimensions of space

and one dimension of time moving forward as that fourth dimension. And general relativity talks about how space-time itself has a shape to it. A shape that is distorted by all the wonders inside of it. All the beautiful stars, planets, galaxies, black holes. Their distortion of space time is gravity. And if you push that gravity to its extreme, you get black holes. And some physicists theorized that white holes could also exist. And that would be the opposite to a black hole. They'd push out matter instead of consuming it. And the thing that couldn't connect them is a wormhole.

But scientists have never seen one. And as a lifelong Treki, I have long wanted to know, could we ever? Or are wormholes purely science fiction? I think, according to the physics, there is a non-zero chance that we could find a wormhole. So you're saying there's a chance. I think if we find a wormhole, that means someone else created it.

So today on the show, wormholes, the geometry of space time, and how to a theoretical physicist, If the math checks out, you can't rule it out. I'm Regina Barber, and you're listening to Shortwave, the science podcast from NPR. Okay, Ron, let's start with hard stuff today. Honestly, because before we can talk about, like, fun wormholes, we kind of need to talk about Einstein's theory of general relativity. And this seems like kind of jargony, but it has been talked about in movies.

Can you help us out? Can you summarize the theory of general relativity? General relativity is, in a nutshell, it is geometry. Cubs, we're thinking about spheres, cylinders, pyramids, pyramids, tetrahedians, pick your favorite geometry. Yeah. But there is a specific set of dimensions where general relativity works and it does not. We have found that in dimensions of three, so we're talking about XYZ, up, down, left, right, and the added dimension of time, right?

Physics tends to work, or our reality tends to be well-behaved, like a well-behaved child, right? But the difference here is that general relativity describes these geometries using curved surfaces or curved space time. How does event A and event B relate to each other through a curved surface? which is just a webbing of multiple events in between the two. So you can think of... Like a planet going around, like Earth going around the sun. Earth going around the sun, you know, if the Earth has mass, the sun has mass, the Earth is actually going to be more attracted to the sun.

They both will pull on each other, but the Earth sits in the curved surface that the sun creates, and that's why we're being attracted to it. That's general relativity in a nutshell. Yeah, like the things at the mall where you put the coin in, that's what I would always say to my students. It is a perfect example. Thank you. Thank you. Okay.

Space is curving and one consequence of like that curving is wormholes. Like, can you describe a wormhole? So very plainly, I would kind of describe the wormhole like a subway tube. So you get in on one side. So let's say you're getting in on Penn Station in New York. and you get off at Grand Central. But the in-between, right? So just like the subway is going underground,

the wormhole is kind of like what we call like a hyperspace. So you're not actually, you know, traveling like if you were on the surface. You're kind of tunneling through space time itself and then coming out on another side. So it's a very weird kind of like physical attribute. Oh, I love it. Okay. And like we said earlier, right, like the tunneling of a warmhole. hole is this connection from a black hole that consumes matter to this like theoretical white

hole that pukes out matter somewhere else in space. Yeah. This image is like hard to reconcile with like the classic way teachers describe space time, like this 4D stretchy sheet. Like think of this trampoline material with like a bowling ball in the center and that's like a star in space time. Like how do you feel about this like stretchy sheet metaphor? I think the rubber sheet analogy is a scam. I think it's because it doesn't actually.

So again, like our definition of general relativity, it doesn't give you the accurate description. This is an introductory to curve surfaces and things like that. Yeah. But it doesn't actually show you the dimensionality of space and time. Okay. So instead of using the rubber sheet, I tend to use putty. You can ball it up into whatever shape you want

and then deform it and curve it and spin it around. And now you're getting all of the physics that's kind of involved in the different configurations of space and time, which is general relativity. Yeah. And maybe like another complication, like for people who have heard it is this idea that black holes are like potholes in the fabric of space time. And we've said it before on the show because it's a great way for scientists to convey this like huge amount of gravity. But in a conversation about wormholes, maybe it's too simplistic. It's better to think about a black hole as a sphere. This is why, again, I say that the rubber sheet analogy is a scam because we assume that black holes are actually holes in space, they're not.

They're spheres. And so they're actually squished spheres because they're rotating, right? Like an interstellar that artist's image. Just exactly like an interstellar. Yeah. So it's a great image. And we've seen these. We've taken pictures of black holes and galaxies and seen that these are circles.

These are spherical objects. Wow. And so then the next thing would be, okay, for a wormhole, what would it look like if I entered a wormhole from one side? Would it be a hole or would there be just some tube sitting in space? Well, no. It would be one sphere connected to another sphere. Okay, I love that image. It's like a dumbbell.

But why are people so resistant to like wormhole's existence? Like, why would we not see one in nature? So one of the requirements for a wormhole is you need exotic matter. So like not regular matter that clumps to itself. Yeah. So you need matter that's pushing out. You need matter to keep the wormhole, so to speak, open. And that means that that is matter that's not trying to clump together, like our matter that we know of.

You know, if you drop a ball, it's going to fall towards the earth. But this matter, if you drop a ball, it will repel. It will go in the opposite direction. And so it's like anti-gravity. It's like anti-gravity. But in a sense that we would need, you know, we are very weird atoms or something to hold the wormhole together. Hold it together and keep it open. So you need a force, you know, if you will, to push against the fabric of space time to hold it open so that you can go through.

Right. The other thing is, is that you need kind of like, so to speak, a, I would say like a fake extra dimension so that you can travel from point A to point B. If point A is in four dimensions and point B is in four dimensions, how do you get from A to B if you only have four in between, right? So you would need kind of like an extra dimension to travel through and then fall back down into four. So like the wormhole itself is a fifth dimension. It could have a fifth dimension, right, so that you can have the ability to travel through it. And this is where we get the idea of like hyperspace. What?

Star Trek, Star Wars. It's all in there. They went to a hyperspace that was an extra dimension larger than the one that they actually lived in. Wow. To travel from point A to point B. Yeah. So I remember reading that, like you were saying, you need this like weird matter or energy to keep wormholes open because they're going to collapse otherwise. So if we were to detect a wormhole, someone from like a different alien civilization would have had to make it.

Somebody, yeah. Why would somebody have to make a wormhole? Like, civilization. Yeah, it's entirely based on our understanding of our reality. And so according to physics and the standard model of everything, right, we have not seen any possible evidence or any clues the way matter behaves to suggest that there, would be exotic matter without it escaping to use for us specifically that wormhole. So that is why, you know, most people, if you ask them, well, what would happen if we found a wormhole?

That means, well, we found evidence of another civilization. Wow. Or we put it there from the future, right? Which is another possibility. But all in all. I love talking to theoretical physicists. Like, anything's possible. It could be.

But all in all, it does suggest that something created it and not it being kind of naturally occurring because it seems unnatural to exist. So we're talking about all these like possibilities, right? You would have to find this exotic energy, this exotic matter. But like, so what is the main skepticism? When you're talking to astronomers, when you're talking to other scientists, what is the main reason why wormholes is someone? something that's kind of still in like the outlier research topics. Yeah. It's mainly because we can't test it.

So it's still kind of looked at as like a science fiction. I wouldn't say it's fringe because we have, you know, real mathematical solutions that we can, you know, kind of simulate, if you will. But in terms of something being viably testable, because that's the scientific method, we have to recreate it, you can't test for a wormhole. You can't even create one experimentally. And so that is, I would say, the pushback or the, you know, the grief against wormhole research is that, you know, this is, it seems like it is decades, if not centuries of technology ahead of us. And so then the question is, well, why would you study wormholes?

Well, I would say, why would you not? Why not? That is, you know, that's kind of giving us another clue about how our universe could behave. And then giving the fact that we've only seen 5% of our observable universe, the other 95% could have wormholes in it. And we just not looked hard enough. For you, why is it so important to not rule out these mathematical solutions to general relativity? Because at one point, space travel was fiction. At one point, the cell phone was fiction. You know, the computer was fiction.

Quantum mechanics was fiction. So I look at, you know, all of these theories, and this is kind of my motivation as a theoretical physicist, is that someone has to work on these problems, but do it creatively to generate the advancements in technologies decades later. And so that is why, you know, I work on black holes and jet physics and things like that. And why one would work on wormholes? Because we need somebody to solve these very, very fundamental or basic problems and do it creatively and innovatively, right, so that we can have something to advance our technologies to later on. Ron, thank you so much for talking with us today. I've become slightly more hopeful for the existence of wormholes. That's great. Thank you for having me. This was fantastic.

This episode was produced by Burley McCoy, edited by a showrunner Rebecca Ramirez, and fact-checked by Tyler Jones. The audio engineer was Jimmy Keely. Betz Anovan is our senior director, and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Shorewave from NPR.