Warp drive isn't science fiction!
Some science fiction is science fiction. For example, H.G.Wells ‘War of the Worlds’ is science fiction as it involves spaceships that travel from Mars to Earth and attack with heat rays, which is scientifically credible. John Wyndham’s ‘The Day of the Triffids’ is also science fiction as it involves genetically altered plants, bred for fuel, that go on the rampage after Earth’s populations is blinded by a rogue satellite, which is also fine. Interestingly, Kazuo Ishiguro’s ‘Never let me go’ is also science fiction as it involves a boarding school containing children destined to donate organs. All of them would go into the science-fiction shelves.
But the thing is, I found out this week that travelling between the stars in a practical length of time is theoretically possible after all.
As mentioned above, Einstein's Theory of General Relativity makes it clear that you can't move a physical object through space at a speed faster than light. This is because when you accelerate an object through space-time, you increase its relative mass. As Einstein pointed out in his famous equation E=mc2, energy and mass are two side of the same coin. Acceleration increases energy and therefore the effective mass. As an object approaches the speed of light, its mass heads towards infinity and so it becomes impossible to accelerate it further.
But there's a trick. What if you manipulated space-time, the fabric of space, around a central area? What if you compressed space in front of that area and expanded space behind it? This would effectively cause that area of space-time to move in relation to the larger world around it but inside that area, nothing would actually be changing. The process would effectively consist of moving a patch of space-time intact through the larger cosmos. Here's a neat picture to demonstrate the idea:
This idea was postulated in a scientific paper by Miguel Alcubierre from the Department of Physics and Astronomy, University of Wales (which is where the above picture originated). As Miguel says in his introduction to the paper:
[In this paper] it is shown how, within the framework of general relativity and without the introduction of wormholes, it is possible to modify a spacetime in a way that allows a spaceship to travel with an arbitrarily large speed. By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it, motion faster than the speed of light as seen by observers outside the disturbed region is possible. The resulting distortion is reminiscent of the 'warp drive' of science fiction. However, just as it happens with wormholes, exotic matter will be needed in order to generate a distortion of space-time like the one discussed here.
The last sentence of the above quote is key; 'exotic matter will be needed in order to generate a distortion of space-time like the one discussed here'. In other words, it might be theoretically possible for someone to go shuttling around the galaxy on their own personal space-time skipping stone, but how are they going to find the energy to do all that space-time warping? They're sitting in a small patch of space-time. What are they going to do, carry a personal, mobile sun around with them?
Fortunately, another piece of modern scientific theory comes to the rescue. Quantum physics tells us that empty space isn't really empty. In fact, every small smidgen of empty space holds enough potential energy to boil all the oceans of Earth. This is known as the vacuum energy or zero-point energy. Theoretically, if someone could create an engine that could draw out some of that vacuum energy and use it to warp space-time around their craft, they would be able to travel between the stars in hours or days. Warp drive travel is therefore possible; they could even take a cocktail bar with them.
Time for a summing up. I used to think that warp-drives weren't science-fiction, even though everyone was under the delusion that they were. I now realise that a warp-drive isn't necessarily science-fiction, as it's theoretically possible that such a device could be built, and therefore a warp-drive can be part of science-fiction, as it's a story element that's based on solid science. Therefore, although it was, I thought it wasn't, but now I think it is, as it's possible that it isn't. I hope that makes sense.
All of this means that I can now watch Star Trek with a relaxed and niggle-free mind, at least if I ignore another question; if it's the twenty-fifth century and humanity is beyond petty tribal issues and small-minded, shallow concerns like money and vanity, and their ships are incredibly advanced technical marvels, why do the crew of the Starship Enterprise all wear clothes?