In a word: no. This is because in Relativity physics the phrase "faster than light" has no more meaning than the phrase "slower than stopped". Speeds faster than that of light simply cannot exist.
What does one mean by the concept of "speed"? There are two ways of defining it.
(1) What we might call "static speed" is arrived at as follows: you set up two markers a known distance apart and simply measure the time a moving body (train, bullet, spaceship) takes to get from one to the other. You then divide the distance by the time and call that the speed. Your markers might be, say, 400,000 km apart (e.g. two satellites with laser ranging). If a passing asteroid takes 2 seconds to fly from one to the other (at constant speed, and with the time measured in your own frame of reference), then you divide 400,000 by 2 and say it was passing at 200,000 km/sec. If another asteroid can be found that takes only one second to fly from one to the other, then you say it was passing at 400,000 km/sec.
Actually, according to the equations of Relativity no physical body can go at 400,000 km/sec, since this is greater than the speed of light (300,000 km/sec). So you have a paradox: 400,000 km/sec is a perfectly well-defined speed, if anything ever went at this speed then you would be able to recognise it, yet the theory tells you that nothing ever could (unless it had always travelled faster than light).
(2) The other way of defining speed is to measure the amount of acceleration it would take you to catch up with a moving body (at constant acceleration, just multiply your acceleration by the time required to accelerate up to match the speed of that moving body). We might call this "dynamic speed", since the measurement requires us to do something dynamic rather than simply sit around watching.
Now for the crunch. In Newtonian spacetime both static speed and dynamic speed amount to exactly the same thing. This is because the geometry of Newtonian spacetime is real, i.e. both space and time are measured in so-called "real" numbers.
But Relativity is based on Minkowski spacetime, and here static speed and dynamic speed are different, and the greater the speed the more different they are. This is because the geometry of Minkowski spacetime is complex, i.e. space is measured in so-called "real" numbers, while time must be measured in so-called "imaginary" numbers.
The definition of relative speed natural to Minkowski spacetime is not static speed, but rather dynamic speed. Furthermore, this dynamic relative speed is represented on the space/time diagram as an imaginary angle; the corresponding static speed is then the tangent of this angle.
Is a right-angle in ordinary geometry a finite quantity or is it infinite? If you measure it in degrees, it is finite: 90°. But suppose you measure, not the angle itself, but the tangent of the angle. As the angle approaches 90°, so the tangent goes off to infinity. So: where angular measure is concerned, a quantity can be both finite and infinite at the same time depending upon how it is defined.
And so it is in physical spacetime. The static speed of light relative to any observer is finite: 300,000 km/sec. But speed appears naturally in Minkowski spacetime not as a linear measure but as an angle -- the imaginary angle between two world-lines. This angle can increase without limit, and in particular the dynamic speed of light is infinite.
The speed of light on the Minkowski space/time diagram is infinite, because it uses dynamic speed, not static speed. That diagram represents the physical world more accurately than its Newtonian equivalent. Therefore no spaceship in our universe can ever travel faster than light.
(This is not how physics textbooks present the matter -- at least, the textbooks that were current when I was at college a few years ago. Either, therefore, the writers of those textbooks had not stumbled upon the most natural way of explaining the matter, or they had a vested interest in keeping the subject hard to understand.)
To put it another way: if you draw a space/time diagram, with rays of light running at 45° to the axes, then a line at say 44° to the time axis represents someone travelling very fast indeed relative to you. But a line at 46° to the time axis represents that same someone's space axis (properly, space hyperplane). There is nowhere on the diagram to place the world-line of anybody travelling "faster than light" relative to yourself: all such lines are spacelike lines, not timelike ones.
If there are any universes adjoining our own in hyperspace and in which the speed of light is greater than in our own, allowing spaceships to take short cuts, then nobody has the slightest idea how to reach them or even detect them! That sort of speculation belongs in "Star Trek".
But in any case we don't need to break the light barrier! Starships cruising at around 10 per cent of light speed are perfectly conceivable, powered either by nuclear fusion (the low-tech version, though still a century or two ahead of us), or by solar energy stored in the form of anti-matter (the high-tech version: we can see that the laws of physics allow such an engine in principle, but have no idea how to make it work in practice). They would take decades to reach a nearby star system, but by then human lifetimes may well have been extended, making the long voyage not such a big deal.
The great milestone in the study of fusion-powered starships remains the Daedalus Report, by Alan Bond, Tony Martin and others, and published by the British Interplanetary Society as long ago as 1978. That report contains sketches of a suitable stardrive engine in considerable technical detail, plus an analysis of where to obtain deuterium and helium-3 fuels to power it.
Recent speculations on an anti-matter drive may be found in Marshall Savage's inspirational book, The Millennial Project (Little, Brown and Co., 1992 and 1994).
Stephen Ashworth
9 September 1998
Note: this article has been written by someone who failed his physics degree! But I still maintain I do understand the theory of Relativity. -- S.A.
Last revised 9 September 1998 / 29th Apollo Anniversary Year