When ranking “Wouldn’t it be great if we had these?” science fiction inventions, innovations and imaginations, flying cars would certainly be #1, followed closely by the thing that would make flying cars able to traverse the universe – wormholes. While Albert Einstein had nothing to say about airborne autos, he influenced the possibility of wormholes with his theories of special relativity and gravity. Since the existence of such a time-space warp requires massive power, they’re often linked to the supermassive black holes that exist at the centers of galaxies. Now, a group of scientists have figured out a way to test whether Sagittarius A* (Sgr A*), the Milky Way’s central (and still hypothetical) black hole is also a wormhole. Is someone on the other side doing the same thing? Have we seen this movie plot before?
“If a wormhole smoothly connects two different spacetimes, then the flux cannot be separately conserved in any of these spaces individually. Then objects propagating in the vicinity of a wormhole in one space must feel the influence of objects propagating in the other space. We show this in the cases of the scalar, electromagnetic, and gravitational field. The case of gravity is perhaps the most interesting. Namely, by studying the orbits of stars around the black hole at the center of our galaxy, we could soon tell if this black hole harbors a traversable wormhole.”
That’s the abstract of “Observing a wormhole,” a new paper, published in Physical Review D, written by Dejan Stojkovic, PhD, cosmologist and professor of physics in the University at Buffalo College of Arts and Sciences, and De-Chang Dai, PhD, of Yangzhou University in China and Case Western Reserve University in Cleveland. Stojkovic and Dai didn’t just observe Sgr A* -- they also watched S2, the star orbiting the black hole. Unlike in Interstellar and other wormhole movies and novels, these physicists don’t believe humans in giant, extremely tough spaceships can travel through a wormhole. However, something much large can, and it could also use its gravity to influence something equally large on the other side. Enter S2 and its possible opposite-galaxy twin.
“In particular, with a near future acceleration precision of 10-6 m/s2, a few solar masses star orbiting around Sgr A* on the other side of the wormhole at the distance of a few gravitational radii would leave a detectable imprint on the orbit of the S2 star on our side. Alternatively, one can expect the same effect in black hole binary systems, or a black hole–star binary systems.”
In other words, unusual movements by a giant star near a supermassive black hole could indicate that the black hole is actually a wormhole. And Stojkovic and Dai measured S2 and found it shaking hard enough to make them shake at the discovery of an actual wormhole … right? RIGHT?
“When we reach the precision needed in our observations, we may be able to say that a wormhole is the most likely explanation if we detect perturbations in the orbit of S2,” he says. “But we cannot say that, ‘Yes, this is definitely a wormhole.’ There could be some other explanation, something else on our side perturbing the motion of this star.”
As Stojkovic indicates in a University of Buffalo press release, current technology is not precise enough to see the movement, nor have they been observing S2 long enough to determine if it has actually moved in a non-standard way. On the good news side, Stojkovic believes this technology will be available in a within-our-lifetime period – possibly in a decade.
What if S2 never moves? That doesn’t necessarily mean Sgr A* isn’t a wormhole, just that there’s no giant star on the other side. It also doesn’t mean that something smaller couldn’t make a trip through it, although the ‘negative energy’ required to accomplish it is still considered to be impossible, even at the particle level.
So then, why keep looking at S2 and Sgr A*? Astronomers, like cryptid hunters, are on a quest. As Stojkovic told Popular Science:
“If one worm hole is found, then there is no reason to believe that there aren’t many others, When we found the first candidate for a black hole, then suddenly we saw millions of them.”