Chethana Janith, Jadetimes Staff
C. Janith is a Jadetimes news reporter covering science and geopolitics.
Interstellar Travel Is Possible If We Break Into a Higher Dimension, Scientists Say..
And luckily for us, quantum physicists think they know how to reach that higher dimension.
In the 2014 film Interstellar, humanity takes advantage of a wormhole near Saturn to travel to different galaxies in minutes while searching for a new, habitable planet. Similarly, a network of wormholes allows people to jump instantly between distant planets in the science fiction series Stargate. The iconic show Star Trek is rife with wormholes that connect humans and aliens across distant parts of the Milky Way galaxy in seconds.
Whether natural or constructed, wormholes seem to be the perfect gateway to traverse distances that would otherwise take hundreds or even tens of thousands of years to cross, even at the speed of light. Wormholes seem to be studded all over outer space like space elevators that are just waiting to speed us along to interstellar destinations. Scientists think that if we could break into the higher dimension in which wormholes probably exist, we could make traveling to the stars a reality.
But in real life, wormholes exist only on paper. No telescope, particle accelerator, or distant satellite has provided evidence of an actual wormhole. Yet the math indicates that a wormhole could be as real a spacetime phenomenon as a black hole. After all, sixty years ago, black holes were considered to be pure speculation; now, we have astronomical evidence for them.
In much the same way, some astrophysicists think we could detect evidence for wormholes if our technology advances enough. In 1935, Albert Einstein and his colleague Nathan Rosen mathematically demonstrated a concept, later dubbed an Einstein-Rosen bridge, that built upon General Relativity Theory principles and indicated the possibility of a shortcut through spacetime. In 1957, physicist John Archibald Wheeler gave the concept the name “wormhole” for a particular warping of spacetime.
According to General Relativity, space and time are tangled together in a “fabric.” Its properties dictate the movements of all interstellar bodies, such as planets, stars, and galaxies, because the mass of these objects causes all of spacetime to curve. In fact, this curvature is what we feel as the force of gravity. To picture what a wormhole does, imagine a scarf with an ant at one end. The scarf is perhaps six feet across, and the ant would spend a few minutes crossing from one side to the other. Now imagine picking up both sides of the scarf and folding them so the opposite ends are close together. In the middle, place a cardboard tube connecting the two sides. Now, the ant can traverse the scarf’s length in mere seconds.
If the scarf represents the fabric of spacetime, this extreme warping would cause two distant places to effectively pull together much more closely, connected by a bridge that occurs in a higher dimension—our wormhole. If you travel through this portal, you’d come out on the other side far more quickly than you would if traveling the normal “length” of spacetime. One theory says if our technology were to combine exotic matter with a black hole, we may create a wormhole. Exotic matter is hypothetical at this point, described only in mathematical terms. It acts in unexpected ways, like having negative mass and working in opposition to gravity. Perhaps the other side of a black hole, which pulls in all matter and even light, spits out all of it on the other side, which astrophysicists sometimes call a white hole.
Because space and time are inextricably linked, wormhole travel causes not only a shortcut through space, but an usual distortion of time. Time might speed up, slow down, or even loop, putting you at a point before you even started your journey, or giving you the ability to visit the future when you emerge on the other side of the wormhole. The trip might seem to take seconds to you, but an outside observer could wait for years to see you again. The more you fold spacetime in on itself, the faster you’ll reach the other end of the wormhole; warp spacetime enough, and the entire journey would be like stepping through a doorway, practically instantaneously.
To actually access a wormhole, scientists want to turn to quantum physics, the study of how the universe behaves at the smallest scales. Quantum physics principles theorize that microscopic wormholes probably already exist. They don’t appear for long, popping out of the universe like soap bubbles, but they are an inherent property of a theorized virtual particle called quantum foam. To construct a stable wormhole at a size practical for travel, advanced technology might need to catch hold of one of these microscopic wormholes, enlarge it somehow, and then keep it open for travel.
Let’s say an advanced civilization creates a wormhole in space - something theoretical astrophysicist Kip Thorne, Ph.D., says is pretty unlikely, but more likely than a stable, travel-friendly wormhole appearing spontaneously. Now you can ignore the speed limit of the universe, so you approach the wormhole. That’s when you encounter your first problem.
As you get closer, gravity keeps increasing. Because you are riding in a special spaceship constructed to withstand the gravitational forces of the wormhole, you can enter knowing your ship won’t be shredded. But the intense tidal forces inside still buffet your ship around. It’s the bumpiest ride ever. Inside, you see otherworldly distortions and swirling lights around you, due to gravitational lensing, because gravity is so strong it’s bending every bit of light. The extreme g-forces steal your breath. You experience odd sensations due to the ultimate warping of space and time.
You close your eyes and hang on. Now, another problem: there’s a good chance the wormhole will collapse. Theoretically, the matter and energy needed to hold open a hole in the fabric of spacetime is unrealistic, and any naturally occurring wormhole will likely implode just after it forms. Fortunately, the aliens threaded this wormhole with exotic matter to scaffold it and hold it open, an idea Thorne and his colleagues at the California Institute of Technology in Pasadena explored in their 1988 paper about how wormholes could enable time travel.
So how do you know where the other end emerges? And when? To enable time travel, the alien race has already accelerated one end of the wormhole to near the speed of light. The other end experiences a different passage of time because it moves relatively slower. If you entered through the slower-moving end and then exited from the same slower end, you can visit the past. When exactly you end up depends on how fast the endpoint is moving. Faster equals further in time. If you’re not careful, traveling through the wormhole would place you at the other end at a different time than expected.
According to Thorne, who served as a consultant on the science of Interstellar, quantum mechanics could hypothetically explain a way to time travel via wormhole. So far, it’s a thought experiment that leads to the conclusion that you’d lose information along the way, not very practical.
“You get caught up in the so-called information loss paradox,” he explains. Thorne would like to keep following the logic of physics and see what happens, since we can’t actually experiment with wormholes today. But someday we will, Thorne believes. In the meantime, he says, “simple thought experiments … can sometimes dig pretty deeply into the laws of nature.”
