Interstellar, Christopher Nolan’s epic SF adventure, hits cinema screens in a week, hooking viewers with the tagline: The end of Earth will not be the end of us. Provocative stuff. Leaving aside the small fact that, actually, the end of Earth will almost certainly mean the end for the overwhelming majority of us, and the folks who might have a chance of jumping ship and surviving will most likely be rich, well-connected industrialists who’ve played a big part getting us into this mess, the film does bring up the question of how in the hell we might reach other habitable worlds.
Exoplanet discoveries have gone through the roof in the last couple of years, so although we might struggle to find a world just to our liking, its not inconceivable that there are worlds out there that wouldn’t immediately crush/roast/freeze/asphyxiate us. Trouble is, capturing the reflected light of other worlds and traversing the great voids of space to reach these other worlds are two different matters entirely. ET might be able to phone home, but getting him back there is a whole different kettle of alien fish. Light travels fast. Rockets don’t. At least not yet. And trumping even the zippy three times ten to the eight photons flashing across our night skies is the sheer bloody immensity of the cosmos. Even light takes over four years just to reach our closest stellarhood neighbour. And really, who wants to visit the puny little red-dwarf which is Proxima Centauri anyway?
Unless you’re going to go the generation/cold-storage ship route made popular by books such as Alastair Reynolds’ Revelation Space series or Elizabeth Bear’s Dust, you kinda have to cheat. Interestingly though, cheating doesn’t necessarily mean violating the laws of physics. Aren’t the laws of physics great? Just when you thought something was totally iron-clad certain, the universe reveals an extra wrinkle, along comes a superior theory, and BANG you have a little wriggle room, or dead-alive cats, or twins aging at different rates depending on their relative relativistic travels, or, you get the picture…
In Interstellar, Nolan goes the wormhole route as a solution to get us shifting from A to B without having to stop at every intergalactic service station along the way. The concept is pretty simple–in two dimensions. Imagine a piece of paper with two points marked on it. Those points represent two stars. What’s the shortest distance between those two points? A straight line between those points I hear you say? Nope. You need to start thinking “outside the box” so to speak. If you fold the paper over, line up the two stars, and punch a hole through then the shortest distance is zero! Extending the analogy to three-dimensional space i.e. you traverse a fourth dimension, and you have the wormhole concept.
Incredibly, physicists think this might not be impossible to achieve. Wormholes are a natural consequence of Einstein’s theory of general relativity, first named Einstein-Rosen bridges, but require weird material called exotic matter to stay open for any non-negligible length of time. Basically, don’t go buying that sunblock for the trip to Vega just yet.