Faster-Than-Light Travel Could Work Within Einstein’s Physics, Scientist Claims

We’ve wanted to visit other star systems for decades. There’s just one problem: they’re so far away that even the closest one would take tens of thousands of years to reach using conventional spaceflight.

Physicists, on the other hand, are not easily discouraged. Give them an impossible dream, and they’ll come up with a fantastic, hypothetical way to make it a reality. Maybe.

According to a 2021 study by physicist Erik Lentz of Göttingen University in Germany, we may have a viable solution to the dilemma, and it may be more feasible than other potential warp drives.

This is an area that attracts a lot of bright ideas, each with a unique approach to solving the puzzle of faster-than-light travel: achieving a way to send something across space at superluminal speeds.

Hypothetical travel times to Proxima Centauri, the nearest-known star to the Sun. (E. Lentz)

However, there are some issues with this notion. According to Albert Einstein’s theories of relativity, there is no real way to reach or exceed the speed of light, which would be required for any journey measured in light-years.

This hasn’t stopped physicists from attempting to break the universal speed limit.

While pushing matter beyond the speed of light is always a bad idea, there is no such rule in spacetime. In fact, the far reaches of the Universe are already stretching away faster than its light could ever hope to match.

To bend a small bubble of space in a similar manner for transportation purposes, we’d need to solve relativity’s equations to create an energy density less than the emptiness of space. While this type of negative energy occurs on a quantum scale, amassing enough of it in the form of ‘negative mass’ remains a realm for exotic physics.

In addition to facilitating other kinds of abstract possibilities, such as wormholes and time travel, negative energy could help power what’s known as the Alcubierre warp drive.

This speculative concept would use negative energy principles to warp space around a hypothetical spacecraft, allowing it to effectively travel faster than light without challenging traditional physical laws, except for the reasons stated above, we can’t hope to provide such a fantastical fuel source to begin with.

But what if it were possible to achieve faster-than-light travel while sticking to Einstein’s relativity without requiring any kind of exotic physics that physicists have never seen before?

Artistic impression of different spacecraft designs in ‘warp bubbles’. (E. Lentz)

Lentz’s recent work proposes one such method, owing to what he calls a new class of hyper-fast solitons – a type of wave that maintains its shape and energy while moving at a constant velocity (and in this case, a velocity faster than light).

According to Lentz’s theoretical calculations, these hyper-fast soliton solutions can exist within general relativity and are derived entirely from positive energy densities, eliminating the need to consider exotic negative-energy-density sources that have yet to be verified.

With enough energy, these solitons could function as ‘warp bubbles,’ capable of superluminal motion and theoretically allowing an object to travel through space-time while being shielded from extreme tidal forces.

It’s an impressive feat of theoretical gymnastics, although the amount of energy needed means this warp drive is only a hypothetical possibility for now.

“The energy required for this drive traveling at light speed encompassing a spacecraft of 100 meters in radius is on the order of hundreds of times of the mass of the planet Jupiter,” Lentz said in March last year.

“The energy savings would need to be drastic, of approximately 30 orders of magnitude to be in range of modern nuclear fission reactors.”

While Lentz’s paper claimed to be the first of its kind, it was published almost exactly at the same time as another recent study, also published in March 2021, which proposed an alternative model for a physically possible warp drive that does not require negative energy to function.

Both teams made contact, according to Lentz, and the researcher intended to share his data further so that other scientists could explore his findings. Lentz also went on to present his findings to the public through a YouTube livestream.

There are still many mysteries to solve, but the free flow of these kinds of ideas is our best hope of ever visiting those distant, twinkling stars.

“This work has moved the problem of faster-than-light travel one step away from theoretical research in fundamental physics and closer to engineering,” Lentz said.

“The next step is to figure out how to bring down the astronomical amount of energy needed to within the range of today’s technologies, such as a large modern nuclear fission power plant. Then we can talk about building the first prototypes.”

The findings were reported in Classical and Quantum Gravity.