Interstellar Travel Is Possible If We Break Into a Higher Dimension, Scientists Say

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.”