If you want a science fiction epic about the entire galaxy, you need a faster than light trip. The alternative is that it takes decades or centuries to reach an alien galaxy, which isn’t nearly as much fun. So you start with a wild science idea, add a little bit of technobabble and poof! To the stars as soon as possibleEverything from wormholes to hyperspace has been used in sci-fi, but perhaps the best-known FTL trope is warp drive.
Warp drive has been used in sci-fi since the 1930s but was popularized by the 1960s television show Star TrekAlthough it is based on the general theory of relativity, where space and time can be warped by gravity, the TV series did not go into details. Warp coils, mumble mumble, dilithium crystals. It doesn’t matter that the theory of relativity clearly states that objects cannot travel faster than light. Without warp drive, Captain Kirk would never be able to defeat beautiful aliens.
Still, the idea was so intriguing that a few scientists tried to develop a theory of how it might work. For example, physicist and science fiction author Robert Forward suggested several ideas. But things really took off when Miguel Alcubierre published a paper in Classic and quantum gravity that could really be called warp drive.
The paper showed how the general theory of relativity that provided space could be warped in such a way that FTL travel was possible. Theoretically, a ship could never travel by space faster than light, but you could form a warped space bubble around the ship, allowing it to reach distant stars in no time. The idea became known as the Alcubierre ride.
There was only one problem. While the Alcubierre drive was possible within general relativity, it only worked if you could get hold of some kind of exotic material from a planet of negative mass. All known matter has positive mass, so that’s kind of a deal breaker. Even Alcubierre has said the idea probably wouldn’t work in real life.
New research solves some of these problems, but introduces others. Alcubierre and Lobo’s work mainly focuses on the warp effect of the weak field. They find that minor warp effects are comparable to a reactionless drive, as suggested with the EM Drive. They also found that while the propulsion still requires negative mass energy, it could hypothetically be done with a ship of positive finite mass.
Another recent article by Erik Lentz takes a different approach. He notes that there are certain warp configurations that resemble solitons. Solitones are a wave effect that amplifies itself. Solitons can maintain their shape while moving at a constant speed and have been observed in water and other liquids. Lentz showed that while soliton warp bubbles would require an incredible amount of dense matter, there would be no need for the energy of matter to be negative.
Both ideas have another problem. By creating a relativistic bubble around the ship, they effectively isolate the ship from the outside world. This is known as the horizon problem and it means that a ship’s warp bubble cannot be controlled from the inside. The ship’s journey should be controlled from the outside. Jean Luc Picard could be the ship’s captain, but he couldn’t simply “make it that way”.
Clearly, warp drive is still hypothetical. There are deep theoretical challenges, not to mention the technical ones. But maybe we’ll have all of this worked out by the 23rd century, and we can finally turn to the stars quickly.
Reference: Alcubierre, Miguel. “The warp drive: super-fast travel within the general theory of relativity.” Classic and quantum gravity 11.5 (1994): L73.
Reference: Alcubierre, Miguel and Francisco SN Lobo. “Warp Drive Basics.” Wormholes, Warp Drives and Energy ConditionsSpringer, Cham, 2017.257-279.
Reference: Lentz, Erik. “Breaking the Warp Barrier: Superfast Solitons in Einstein-Maxwell Plasma Theory.” Classic and quantum gravity (2021).