Bifrost now a reality, or so

If stabilised and made big enough, wormholes can be used as a viable means of space travel in the future-just as Thor does in the Marvel Cinematic Universe

A team of physicists has created the first-ever wormhole, a tunnel that connects two distant points in space and time. Simply put, it is like the magical Bifrost bridge in Marvel Cinematic Universe movies that allows Thor to travel between his home Asgard and the eight other realms with ease.

The Bifrost is nothing but an Einstein-Rosen bridge, or a wormhole — theorised in 1935 by Albert Einstein and Nathan Rosen. The term “wormhole” was coined in the 1960s by Princeton physicist John Wheeler, who felt Einstein-Rosen bridges were akin to the holes that worms bore through apples.

Before we dive deeper into this mind-bending theory, let’s talk about the aforementioned achievement. Caltech physicist Maria Spiropulu and others, whose research got published in Nature a couple of days ago, claimed they have simulated two tiny black holes on a quantum computer (Google’s Sycamore) and sent a message between them through a tunnel through space-time. They said the model tested by them “preserves key properties of the traversable wormhole physics…”.

The physicists noted, though no rupture of space and time was created in physical space during the experiment, a traversable wormhole emerged like a hologram out of quantum bits of information, or “qubits”, stored in tiny superconducting circuits. By manipulating the qubits, they then sent information through the wormhole.

It was a “baby wormhole”, Professor Spiropulu was quoted as saying by Reuters. But scientists are a long way from being able to send people or other living beings through such a portal. “People ask me, ‘Can you put your dog in the wormhole?’ So, no... That’s a huge leap.”

Then why such hullabaloo about this experiment?

It’s because it is evidence for the holographic principle, a hypothesis that brings together quantum mechanics (the rulebook for atomic and subatomic particles) and general relativity (the description of gravity as a geometric property of the space-time fabric) — the two pillars of fundamental physics. Simply, the holographic principle, as put by American physicist Leonard Susskind, says: “The three-dimensional world of ordinary experience — the universe filled with galaxies, stars, planets, houses, boulders, and people — is a hologram, an image of reality coded on a distant two-dimensional surface.”

But how wormholes may form naturally, not in labs? The simplest wormhole solution was proposed by Einstein and Rosen, who theorised white holes as the polar opposite of black holes (which consist of a singularity, or a point of infinite density, and an event horizon — the region surrounding that singularity beyond which nothing can escape). These white holes, according to them, also have a singularity but work opposite to black holes — nothing can enter the event horizon of a white hole, and anything inside the white hole gets ejected immediately.

Einstein and Rosen said theoretically, every black hole is paired with a white hole and because the two holes would exist at separate points in space, a tunnel could bridge the two ends.

But such a wormhole would be of no use: First, because nothing can enter a white hole; second, nothing can exit a black hole. Also, such a system would be unstable.

Still, a theoretical model by physicist Jose Luis Blázquez-Salcedo — presented in Physical Review Letters — makes traversable wormholes less far-fetched. According to the model, changing the mass and charge of fermions (a subatomic particle) could create a traversable wormhole. But there’s a catch — such a wormhole could be microscopic, far too small for any human.

If stabilised and made big enough, wormholes can be used as a viable means of space travel in the future. In other words, the plot of Christopher Nolan’s 2014 movie Interstellar, which demonstrated traversing a wormhole in one smooth motion, by piercing a pen through two points (near the opposite edges) on a folded piece of paper.

But even if we put aside the technical challenges in traversing a wormhole, humanity doesn’t have “starships” yet. Also, we don’t know what to expect inside a wormhole and where it would take a starship — somewhere in our Milky Way or to the edge of the universe if there’s any.

Even astrophysics pioneer Kip Thorne, on whose real physics the wormhole in Interstellar is based, sounds pessimistic about a traversable wormhole. “If they can exist, I doubt very much that they can form naturally in the astrophysical universe,” he writes in his book The Science of Interstellar.

Not only a shortcut between two distant places in space, wormholes, according to Andrew Friedman of MIT, “could potentially be used as time machines”— again as shown in Interstellar, in which the character played by Matthew McConaughey, while travelling by a spaceship through a wormhole, didn’t age like the other characters on Earth.

But if possible, where would you go through a wormhole? I would request Heimdall to open the rainbow Bifrost bridge so that I could steal the Infinity Gauntlet from Odin’s Trophy Room in Asgard. Oh! It’s fake.