With hyperspace suddenly in the news, here are some thoughts on how taking a shortcut to reach the stars has appeared in science fiction. They’re from The Science in Science Fiction, edited by Peter Nicholls (London: Book Club Associates, 1982), p. 72:
“Hyperspace is the science fictional name for the ‘other space’ used in such short cuts. The word was invented by John W. Campbell for his short story “The Mightiest Machine” (1934) and unashamedly stolen by hundreds of writers since. Today, hyperspace is part of science fiction’s standard furniture — solving all those awkward problems of travel to the stars…
“[One] view of hyperspace is as a ‘universe next door’ much smaller than our own, with every point in hyperspace corresponding to one in this universe. Mathematicians call this a ‘one-to-one’ mapping. So hyperspace behaves like a little map of our own universe, a map which can be visited — as though we could step from London to the point marked ‘London’ on the map, walk a short distance to the point marked ‘New York’, and step out of the map into the real New York. Again, the difficulty is getting into the map — into hyperspace — in the first place.
“This model features in Frederick Pohl’s story “The Mapmakers,” in which (logically enough) an error in positioning of 1 cm on the ‘map’ can bring a ship back to normal space millions of light-years from its planned destination. There is no reason why hyperspace travel should be even this simple. In Bob Shaw’s Night Walk the hyperspace universe has a fiendishly complicated shape, like a mathematician’s nightmare — the odds are that inexperienced travellers will end up at completely random points in our space, and will never get home again.
“Still more depressing is George R.R. Martin’s story ‘FTA,’ where people break into hyperspace and find that it is not a short cut after all. Why, apart from wishful thinking, should it be? In this story, to go via hyperspace takes longer.”
Centauri Dreams‘ take: There’s nothing wrong with being an optimist, and while the Martin story makes for good reading, a determined effort to push the limits of the possible may one day pay off in a true superluminal breakthrough. But the key to this kind of research is to understand that it is incremental, that progress is likely to occur in a series of small steps that build the foundation for the great events that follow, and that this incremental work should be an ongoing process. Everybody hopes for the grand design discovered in a scientist’s papers, one that will turn everything over in the blink of an eye, but getting to the stars is more likely to be a matter of slow, patient physics that keeps probing the nature of spacetime even when the news media have moved on to other topics.
Here’s a little thought experiment for those that believe in higher dimensional travel to consider.
A universe with no dimensions is a non-dimensional point.
A universe with one dimension can have distance. So, let’s consider two points (a) and (b) separated by a given distance (x). The universe is comprised of a line passing through the distance (x) and the two points. The shortest distance from (a) to (b) is (x).
A universe with two dimensions is represented by a plane. Let’s expand our last universe into two dimensions and add a point (d) that lies outside of the vector (x). We can state that the distance from (a) to (d) is (y) and from (b) to (d) is (z). In this universe, the shortest distance from (a) to (b) is still (x).
Let’s move into a universe like our own and give it 3 spacial dimensions. As I think should be apparent, in 3 dimensions the shortest distance from (a) to (b) is still (x).
It seems apparent that adding dimensions does not necessarily provide a means for a shortcut between (a) and (b).
Let’s suppose the universe is folded into a fourth spacial dimension (like you can fold a two-dimensional universe over into the third dimension). Then perhaps, you might have available shortcuts, but only between certain points that are relative to each other from one side of the fold to the other. However, recent investigations indicate space-time is flat…
So, quick trips to any ol’ where, are not likely (even in a folded universe) and trips into a fourth dimension in a flat universe will only add distance to the trip.
Space-time is only flat on a truly universal scale where the vast gravitational effects of galactic clusters can be considered negligable. On the scale of a single galaxy space-time is quite warped–it’s an obvious result from the presence of all those stars, nebulae, and black holes, etc.
On the scales of interstellar travel, then, if the conventional 4-D space-time is warped and the fifth hyperspace is flat, travel through hyperspace becomes the shortest distance. Of course there’s no reason to assume that hyperspace is flat on the scales I’m talking about and since most theories require extra dimensions to be curled to Plank-scale sizes they are not very viable.
Then again, there’s no reason to assume that a fifth dimension would be spatial in nature. Time, after all, is a non-spatial dimension.