Whether Star Wars or Star Trek: When the pilot flips the toggle switch, the stars distort and the spaceship races through space at superluminal speeds. the warp drive makes it possible – at least in science fiction logic. Researchers are also working on this fantastic drive without knowing whether it works. Behind the technology there is also a human longing. What is warp drive and why are we talking about it anyway?
The Warp Drive: Just a Vision?
The warp drive, at least in theory, shoots spaceships through the endless expanses of space. It seems that man would rather talk about this technology than think about the technical physical details. After all, who doesn’t want to reach infinitely distant places in space in a few hours or even minutes?
Because in the stories about Captain Kirk, this propulsion technology solves a big problem: people don’t need cryosleep or multi-generation spaceships to reach the legendary planet Vulcan, for example. If this “class M planet” really existed, it would probably take us several tens of thousands of years to reach it with today’s means.
For comparison: According to the current state of research, Proxima Centauri B is the exoplanet closest to us. It’s a mere 4.25 light years away from us. So, at the speed of light, it would take us 4.25 years to reach it. So far, no spaceship has been able to reach them. In reality, the journey between Earth and Proxima Centauri B would be thousands of years.
And that’s where warp drive comes in, because at FTL, the planet would be about as far away as the nearest bus stop. The problem: We would have to trick Albert Einstein’s theory of relativity. Because this states that an object in the universe can never be accelerated beyond the speed of light. So why are we even talking about this legendary drive?
The curvature of time and space
Albert Einstein not only defined the limits of time and space, but how we could, at least in theory, overcome them. According to general relativity, the universe is a stuff of time and space that can be “folded” by gravity. To understand warp drive, we need to understand the properties of gravitational waves. Like waves, they stretch or contract space-time.
This allows all sorts of conjectures to be made about how a spaceship might move through space. Because the Enterprise’s iconic drive uses this part of Einstein’s theory to overthrow another. Because the speed of light no longer matters if space can be distorted. “To warp” means nothing other than “distort”.
As an example, you can imagine a blank sheet of paper that has a black dot on each edge. The points form locations A and B. The “normal” distance describes the prevailing distance between these two points. By folding the paper so that both points are on top of each other, at least the distance is overcome. If you poke a pencil through one point, you’ll land directly on the second.
The theory of warp drive works precisely with such thought experiments. The drive distorts the room so much that point A and point B are practically around the corner.
And in reality?
It wasn’t until 1994 that the physicist Miguel Alcubierre seriously considered the idea of a warp drive. His theoretical solution is based on a basic equation in which a spaceship compressed space-time in front of it and expanded it behind it. The ship should therefore be in a stable bubble of space-time like in a soap bubble.
But the physicist could not solve one problem. Because the so-called Alcubierre drive only works with “exotic matter”, i.e. a matter. Unfortunately there is no such thing as “negative energy”. It is an aid to simulating stable wormholes and FTL travel at all, as Adam Frank writes on Brighter Side of News.
But in 2021, astrophysicists Alexey Bobrick and Gianni Martre showed that exotic matter does not have to be used for warp drive. For their theory, Bobrick and Gianni only need the two components space-time and energy. Accordingly, all warp drives consist of exactly three components:
- an interior space-time that functions like a passenger compartment
- a shell of material made of positive or negative energy, the so-called “warp region”
- an appearance that seems far enough distant, like undistorted space-time
This tripartition allowed both researchers to understand exactly what had to happen in each of these spaces for the drive to work.
Warp drive: not just wishful thinking
Warp drive may indeed be possible in the far distant future. As Bobrick and Martre show, “normal” matter could already be sufficient for this. This could create a kind of passenger area in a bubble where time passes normally while it curves around the bubble.
But even in theory, this only works below the speed of light. According to the two scientists, the idea behind such a drive is less complicated than feared, but it does not guarantee a great leap of humans into the universe. Traveling faster than light would mean using exponentially infinite amounts of energy. Nobody knows where it’s supposed to come from.
Sources: Big Think, Brighter Side of News, own research