What does a journey through a wormhole actually look like?

A simulated wormhole. Credit: Corvin Zahn licensed under cc-by-sa/2.0/de/
Let’s talk about wormholes. I won’t be spoiling anything to say that the plot of Christopher Nolan’s latest film, Interstellar, hinges on the existence of a large wormhole allowing intrepid astronauts to travel through in search of new worlds to colonize.

In the film, the wormhole is basically just a deus ex machina — a simple plot device to get the main characters out into deep space. Nevertheless the film’s brief depiction of this theoretical concept left me intrigued to know what a trip through a real wormhole might actually be like.

A 2D analogy to a wormhole. Credit: Panzi via Wikimedia Commons

Wormholes are theoretical ‘tunnels’ between two points of space caused by the extreme warping of spacetime.

Albert Einstein’s theory of general relativity describes how spacetime warps around massive objects such as black holes. For a good analogy in two dimensions, think of a dimple on a sheet of fabric.

Wormholes are trickier. In order to create a stable wormhole, theory indicates that some sort of exotic material with negative mass is necessary and so far, physicists have no idea what this might be.

But let’s run with the idea that a wormhole can exist. Did Interstellar get it right?

In the film, the exterior view of the wormhole is gorgeous and instantly reminded me of the Palantír crystal ball from Tolkien’s Lord of the Rings trilogy. We see a glistening sphere showing distorted images of the galaxies that lie beyond the wormhole.

Interstellar’s wormhole, with the tiny, ring-shaped Endurance spacecraft in front.
Credit: Screenshot from the Interstellar trailer.

Turns out this is fairly accurate. I spoke with theoretical physicist, Luke Butcher, at the University of Edinburgh to get his take.

“One thing that struck me as nice was the fact they pointed out that it was a sphere, not a two-dimensional hole,” says Butcher. “Visually, the wormhole struck me as pretty realistic at this point in the movie, when we are still outside.”
Then the Endurance spacecraft flies into the wormhole. Personally, I was really looking forward to seeing how the visual artists depicted the wormhole journey (maybe I’ve been watching too many Doctor Who episodes lately).

What we see in the movie is a journey skimming along the surface of a tunnel, with images of distant galaxies and nebulae (I think I recognized the Orion Nebula) painted on the walls. While it is beautiful in its astronomical majesty, the filmmakers certainly took artistic license.

Cover of Kip Thorne’s
The Science of Interstellar

As Interstellar physics guru, Kip Thorne, admits in his recently published book, The Science of Interstellar, the wormhole interior is an “interpretation informed by simulations with my equations, but altered significantly to add artistic freshness.” Nevertheless he believes the visuals “capture the spirit of a real wormhole trip” and are “fresh and compelling.”

Butcher described to me what physicists think a real journey through a wormhole might be like. He imagines the traveler initially looking forward along the direction of motion — the longitudinal direction. By looking left or right, the viewer sees the perpendicular view. 
“Things will look a bit like you’re traveling down the center of a wide tunnel”, says Butcher. “Directly in front of you you’ll see the region of space you’re heading to, and behind you is the region you’ve left behind.”

“These views would be surrounded by concentric circularly-distorted repeats of the same view, a bit like an Einstein Ring, with the whole sky (of one end of the wormhole) wrapped into a series of rings that get more and more closely packed together as you move your line-of-sight from the longitudinal direction, to a perpendicular direction.”

In other words, a bit like this:
Credit: Public domain via Les Bossinas (Cortez III Service Corp.) and NASA

Einstein Rings are a consequence of general relativity. If light from a background star or galaxy passes near this massive object on its way to us, the observers, it has to follow the curvature of the warped space and appears distorted and ring-like.

Gravitational lensing of a background galaxy by a massive foreground galaxy. Credit: Public domain via NASA.

The effect is similar to light viewed through a curved lens; hence it is more generally known as gravitational lensing. Astronomers frequently observe real Einstein Rings, such as in this dramatic Hubble image of a warped ring of light around a massive red galaxy.

A luminous red galaxy warping background light into an Einstein ring, as imaged by the Hubble telescope.
Credit: Derived from NASA public domain image. 

Corvin Zahn of the Institute of Physics, University of Hildesheim has created some fantastic simulations of what it might be like to travel through a wormhole.

Here a wormhole is seen hovering just in front of the physics building of Tübingen University in Germany, with its other end connected to a beach scene in northern France. Colored cubes and rods highlight the bending of light in the curved space of a wormhole. Zahn’s video takes us on a short trip from Germany to France and back, through a wormhole with a very short ‘neck’.

For more information and other cool spacetime videos, read Zahn’s Flight through a Wormhole article and check out his Space Time Travel website.

So there you go. A trip through a real wormhole would probably look surreally bizarre thanks to all the complex paths that light can take around its warped geometry. No need for artistic license when the physics is just as striking!

But until we actually discover a wormhole, such a journey must sadly be left to the realm of simulations and science fiction.

By Tamela Maciel, also known as “pendulum”

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