Faster-Than-Light Travel? Yes Please!: an article by: Rosie Oliver.
We humans hate long boring journeys. So much so that we’ve gone from using horses and carriages to travelling by cars and trains and then onto whizzing around in airplanes. Now the planets, stars and beyond are calling to us.
The distances to reach them are vast. The scenery along the way is mostly empty of anything interesting. We want to get from Earth to anywhere else in our galaxy super-fast. Unfortunately, there is a snag. The laws of physics state nothing can travel faster than light.
What about tachyons, I hear you ask? They were proposed in the 1960s as particles that always travelled above the speed of light. However, that theory was soon disproved. Physicists still use the term today, but it describes the ‘excitations of a quantum field with imaginary mass’. Yes, well, that is quantum physics for you.
This does not stop us from dreaming about whizzing through space at high superluminal speeds. Science Fiction is littered with ‘methods’. How they work are usually described in a short sentence or two, a kind of ‘hand wavium’, and most have problems authors avoid mentioning.
The ideal fictional method of travel is to throw a switch one instance and be comfortably at your destination the next, no matter how far away. This is best known as the jump drive, as used in the 2004 series of ‘Battlestar GalacticaI.
Nice idea, but what is to stop the jump drive dumping the spacecraft in the middle of hard rock or the molten centre of a star? The pilot has to know where the ship is going to and whether it is safe to arrive there. This is the ‘look before you leap’ issue and the only way to obtain the necessary information is at sub-light speeds. Another issue is even the sparsest of intergalactic space has hydrogen atoms and radiation from stars. A spacecraft jumping anywhere would have to dislodge or somehow absorb what is at the destination.
One very theoretical suggestion to overcome these issues is to send the matter and energy at your destination back to your jump’s launch point. Of course, the launch point would have to be in space away from other humans just in case the starship lands in the middle of star and sends back molten plasma or some other disastrous material or radiation. But how would the jump drive know what to transfer back before it has arrived? If it has to arrive first, we are back to the problems mentioned above. In many ways this points to some kind of control that can instantaneously determine what is at both the launch-point and the destination, using some functionality of a kind of hyperspace. In particular, it would require a physical control device to be sited in hyperspace, which of course means some sort of hyperdrive to get it there.
Science Fiction uses the hyperdrive more conveniently to move a spaceship from one place to another through hyperspace at what would appear to be faster than light speed in our normal universe. Hyperspace is named after the idea that it is extra-spatial dimensions overlaid on top of our universe. For the hyperdrive to work, the useful extra dimensions are not defined by straight axes, but rather some form of curved axis to enable the spaceship to take a shorter travelling distance before returning to our universe. The hyperdrive as an idea has been around since at least 1928 with Kirk Meadow’s ‘The Invisible Bubble’. Hyperdrives continue to be a popular faster than light travel method as is seen in Gareth L Powell’s ‘Embers Of War’ trilogy and of course, the ‘Babylon 5’ TV series.
Are hyperdrives realisable? There are many big assumptions behind this idea that remain to be proven, including that extra dimensions exist, they are conveniently curved for travel and that hyperdrives can slip into and out of these extra dimensions as required by the story. It is perhaps not surprising that the idea of hyperspace has become vaguer over time.
Both jump drives and hyperdrives have severe issues in becoming realisable in reality. What of other faster-than-light travel methods suggested in Science Fiction?
Wormholes are sort of an alternative way to skip between places. They act like shortcut tunnels between distant points in the universe. If there are sufficient of them scattered about the universe, they can be thought of as a disjointed railway network across the cosmos. The method of travel has proved popular in Science Fiction, from Joe Haldeman’s ‘The Forever War’ to James SA Corey’s ‘The Expanse’ and beyond. This method is so convenient to both the fiction author and the story’s protagonists. Could wormholes become a reality?
They are viable solutions of Einstein’s General Relativity theory. They come in several forms. While the earliest known types, Schwarzschild and Einstein-Rosen, have proved to be too unstable to be useful, later discovered types are more promising. Researchers have now modelled a transmitted message through one that has remained stable. Still a long way from realising physical wormholes able to transport humans especially without stretching them in the process. Yet, progress is being made. Maybe one day, in the distant future, travel via wormholes will become a reality.
Another kind of network system for faster than light travel currently popular among Science Fiction writers is using quantum entanglement. Yes, the thing Einstein described as ‘spooky action at a distance’. ‘Quantum entanglement’ is one of those phrases that is bandied about in the media without being really understood. Basically, if you measure a property of an entangled particle, then you immediately know the property the other entangled no matter how far away immediately. Yes, information appears to travel faster than light and, this is the point, experiments have proved that information and at microscopic distances, energy, that can be transferred this way. Transporting objects, molecules, atoms or any quantum particles by this method could be thought of as teleportation that is another popular transport mode in Science Fiction. However, this method still belongs to fantasy, at least for now.
Transporting someone across the distance using quantum entanglement would have to be done by reducing them to data or energy, sending the data or energy via quantum entanglement and then rebuilding the person at the destination from the data or energy. This begs a lot of issues. For instance, do the combined processes of measuring the person at the launch point and rebuilding the person at the destination take longer than the more normal travel at sub-lightspeed? Does the whole process mean that there are now two identical people in the cosmos or is the one at the launch point killed? If all the processes operate as designed, how accurate is the reproduced person at the destination? Putting it another way: will the errors that inevitably happen in measuring make a significant difference to how the person would be and act at the destination? This is before considerations are given to the consequences of exceeding the limits of causality, the going back in time to kill your grandfather paradox.
If and it is a very big IF these issues can be overcome, then Peter F Hamilton’s ‘Salvation’ trilogy gives a good description of the way how such a system of sending and receiving stations using the quantum entanglement method can be deployed and used.
One final faster-than-light network system of note uses the Krasnikov tube. In essence, it warps spacetime into a permanent superluminal tunnel. This can be considered as a continuous tube through space whereas the wormholes act as shortcuts. Despite these being identified as a faster-than-light travelling mechanism in 1995, very little has if anything has appeared about them in Science Fiction
These faster than systems, jump drive, hyperdrive, wormhole, Krasnikov tube and using quantum entanglement, will have various detrimental effects, such as very high acceleration on the human body that need to be countered. It should be noted that the much-described stretching effect of a wormhole on a body in Science Fiction seems to have been somewhat mitigated by finding stable wormholes.
So far I’ve talked about methods that need some form of extra-infrastructure to allow superluminal travel. One that does not is warp drives, as made famous by ‘Star Trek’ though the term was first coined by John W Campbell Jr in his 1931 serialised novel, ‘Islands Of Space’.
In fact, ‘Star Trek’s warp drives inspired Miguel Alcubierre in 1994 to find a theoretical solution to Einstein’s theory of general relativity to travel at superluminal speeds. It works on the principle of distorting the fabric of space so the spaceship can travel in a bubble at sub-light speed, which allows Einstein’s lightspeed law to remain unbroken.
Science Fiction had moved to the theoretical possible, but can theory be made into reality?
Every scientist who could had and continues to have a go at sussing this out. There are those who point out problems with Alcubierre’s theory, like the enormous amount of energy needed to make the drive work, down to the equivalent of three Solar masses at the time of writing. There are others who nibble away at these problems towards making the warp drive actually work in practise. However, there are major obstacles that do not yet seem amenable to being solved by engineering alone.
The headline headache is the need for not only a lot of energy, but it being negative energy. A popular suggestion to supply this is via the Casimir Effect, a quantum physics phenomenon that can produce very small quantities. There is a catch: it is negative energy with respect to vacuum energy which itself is a positive quantity. So, it is not really the negative energy as needed by the Alcubierre Drive. This is the bad news. The good news is there are quantum phenomena that are being investigated for their negative energy. It is a case of ‘watch this space.’
There is one aspect of using a faster-than-light Alcubierre drive to be considered: the limitations of the human body. People can quite happily travel at 1g. It would take a year at this acceleration to reach lightspeed, in which time travel in a straight line would get you from Earth out into the middle of the Solar System’s Oort Cloud. Then there is the necessary deceleration at the destination. It means it is at least a two-year journey for humans who want experience travelling faster-than-light. This is on top of need to have enough fuel on board for the engines to function continuously for at least two years, which makes it very expensive.
Having said that, from a systems engineering perspective, developing the feasible Alcubierre drive for sub-lightspeeds would give us faster transport than we have at the moment. I suspect that a nations or large corporations will take up this challenge in due course. This will certainly reduce travel times within our Solar System, which in turn will change the storylines of our Science Fiction set there.
There have been quite a few other suggestions for faster-than-light travel modes over the decades, most from Science Fiction and a few from scientists eg EM-drive that in the end proved to be an experimental error. These have shown far less promise or popularity than those discussed above. To detail them and the twists and turn of the development of faster than light concepts would require a book.
The easy way for a Science Fiction author to access faster-than-light travel is for an alien to come along with the technology and let us humans have it. It does not require any explanation about how it works. One slight snag. How did the aliens come up with their faster-than-light method? Some alien has to be the first and they would have followed a similar path to that mentioned above.
There are few things that can be taken away from this article:-
– Science Fiction has inspired scientists to try to work out how to travel faster than light.
– while it is extremely unlikely we will be travelling at superluminal speeds any time soon, there is hope for the long term. The current most promising methods ‘in development’ are Alcubierre drive, wormholes and transport via quantum entanglement.
– Science Fiction writers are going to have to adjust their stories to align with significant advances such as the subluminal Alcubierre drive, which could become a reality sooner than we think.
– a tremendous amount of thought and effort has gone into how we might be able to travel faster-than-light from both scientists and Science Fiction authors. It shows how much we want to do this. It also means that we have probably come up with all that ways it can be done theoretically from the laws of physics as we know them today.
© Rosie Oliver 2023