Faster than light travel… can’t… maybe… can…

Over at the Guardian Damien Walter has written an interesting piece about faster than light travel in science fiction. See here for the article. In it, he encourages science fiction writers to write about how people could experience faster than light travel.

We’ve all seen the traditional filmic view of faster than light travel – stars become streaks / lines emanating from a central point, which is where the spacecraft is heading. When this view was first proposed, we didn’t know any better. It could have been right. It turned out to be wrong. Apparently the light actually blurs to form an omnipresent greyish light. Yet, the latest films persist in the star-streaked effect.

This story has its own lesson. Once something becomes popular in science fiction, it is difficult to shrug the image off when the scientists prove it is wrong. There is a real disconnect between scientists and science fiction writers. Or putting it another way, science fiction readers and writers don’t keep up to date with the science.

But we have seen evidence of what happens when matter goes faster the speed of light in a medium – it’s called Cerenkov radiation, discovered in 1958. This is when an electron travels faster than the electromagnetic waves in a medium. It’s the blue light we see generated in nuclear power stations. We could use this knowledge to help us describe what faster than light travel could be like.

There is one very interesting point about Cerenkov radiation – it was predicted by Oliver Heaviside, the english polymath, in a paper in 1888-89. [Reference: Nahin, Paul J (1988). Oliver Heaviside: The Life, Work, and Times of an Electrical Genius of the Victorian Age. pp. 125–126.ISBN 9780801869099.] 

If Oliver Heaviside could do this kind of thing, then surely others can to? Which means that there can be science fiction writers who are able to foresee what faster than light travel could really be like.

So why don’t we science fiction writers do this?

Let’s look at the recent thoughts / advances in faster than light travel:

  • Tachyons are particles that can move faster than light. They were first proposed in 1962, but most physicists now believe they do not exist because they would break the laws of causality. [Tachyons are not to be confused with tachyon condensation, which does exist, but moves at slower than the speed of light.]
  • Quantum entanglement is where once particles have been entangled, if one particle changes its state, then the other particle changes its state. So you would think that we could have faster than light communication wouldn’t you? There is the small matter of the particles having to travel away from each other as well as other constraints.
  • Quantum tunnelling is a kind of group velocity result where waves can appear to travel faster than the waves they are composed of. However the waves they are composed of still travel at below the speed of light.
  • Spacetime engineering using general relativity has suggested ways, or to be more precise shortcuts, for travelling faster than the speed of light including:
    • transversable wormholes – you need to find a wormhole and then, how do you navigate through it?
    • warp drives – including the theoretically possible Alcubierre’s drive and developments thereof, but would take quite a lot of time and effort to build.

images-1

Going through this list of possibilities looks very depressing, but then I’m reminded that Einstein’s General Theory of Relativity relies on Riemann geometry. That is one heck of an assumption about our universe!

I know from bitter experience what happens when people neglect to acknowledge the impact of such assumptions. So what happens when you break this assumption… um… oh heck… where’s my notebook…

But getting back to the main point of this article, checking the assumptions behind the theories is one way to suggest ways of getting round what is seemingly impossible physics. By taking away the assumption you add into the richness of the world you are building, by saying what is there. From there it is easy to describe things.

So yes, there is room to add more into the faster than light travel science fiction methods. However, it takes people with the understanding of the current faster than light restrictions to understand what is possible and that means people who understand physics. Those writers are few and far between.

So watch this space… (sorry about the pun…)

Advertisements

2 thoughts on “Faster than light travel… can’t… maybe… can…

  1. Hi, Rosie,

    Intriguing thoughts! I’m particularly intrigued by your observation regarding “underlying assumptions.” If the Universe behaves the way Riemann’s geometrical postulates expect it should, then General Relativity follows as a matter of mathematical logic. The trap, of course, being in Riemann’s axiom system.

    Wouldn’t that go right back to Euclid? If one talks about point, line, and plane, are the assumptions of any non-Euclidean system any different from those of Euclid?

    Bringing up another point: general relativity insists on the unity of “space” and “time.” But our assumptions about “point, line and plane” refer purely to our perception of space. A very, very powerful and useful perception for many applications, granted. How far should we actually take those assumptions before we need to re-examine them? In particular, when Euclidean axioms were not intended to include “time”?

    Questioning whether “time” is actually a “dimension” in the Euclidean sense might be fruitful.

    We assume geometry works because so far, it has. On the other hand, Newton’s physics worked pretty well until Einstein came along. Didn’t make Newton obsolete, really. It just limited the applications of Newtonian physics.

    But your article is really about what FTL looks like from the inside. Couldn’t one argue that it looks like whatever your astrogation systems have been programmed to display?

    Very interesting article!

    • Hello Tom,

      Interesting comments, thank you.

      A very simple explanation of Riemann Geometry can be found at http://www.britannica.com/topic/Riemannian-geometry . Basically it is different from Euclid in that in does not accept Euclid’s fifth postulate (the one about the parallel lines going off to infinity with the same distance between them). There are other geometric systems besides Euclid and Riemann.

      However, the assumption I’m questioning lies at the heart of both Euclid’s and Riemann’s, as it so happens (more by accident than design). The idea behind that took my maths lecturer a whole lecture to explain, and that was without a single maths equation being written. So it would be difficult to put it into words here. The best I can is to point you to a wiki page about the lecture’s subject – Lesbesgue Integration – https://en.wikipedia.org/wiki/Lebesgue_integration

      I have never viewed time as a dimension in the traditional sense. It is an independent variable until we define a relationship with other entities, which in the case of general relativity are space dimensions. [Some people confuse dimension with independent variables.]

      I totally agree that astrogation systems could put up whatever graphical interpretations they want to. So yes, we could have these systems display the streaking stars. But if you look outside the window – all you would see is the grey omni-present light. The stars just would not streak.

      I hope this helps.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s