Artist Mark Rademaker has unveiled a set of concept images imagining what a spaceship capable of traveling to other stars in a matter of months would really look like. Although it may look like something from the next science fiction epic and is unlikely to lift off anytime soon, his IXS Enterprise design is actually based on some hard science.
Interstellar travel is one of the most frustrating buzzkills of the space age. Since launched in 1977, the Voyager 1 spacecraft has traveled about 116 astronomical units (1.08 x 1010 mi, 1.7 x 1010 km). At that speed, it would take about 75,000 years for it to travel to the nearest star, Proxima Centauri, 4.3 light years from Earth – and it isn't even going in the right direction.
Science fiction is filled with stories where this annoying limit is avoided by equipping spaceships with warp drives, hyperdrives, and infinite improbability drives. According to current physics, those are pure fantasy because the speed of light can’t be exceeded. This isn't like the sound barrier that just needed good engineering to overcome. It’s sewn into the very manner in which the universe is stitched together. However, some scientists believe that there is a way around that iron-clad limit.
The idea comes from the work published by Miguel Alcubierre in 1994. His version of a warp drive is based on the observation that, though light can only travel at a maximum speed of 186,000 miles per second (300,000 km/sec), spacetime itself has a theoretically unlimited speed. Indeed, many physicists believe that during the first seconds of the Big Bang, the universe expanded at some 30 billion times the speed of light.
The Alcubierre warp drive works by recreating this ancient expansion in the form of a localized bubble around a spaceship. Alcubierre reasoned that if he could form a torus of negative energy density around a spacecraft and push it in the right direction, this would compress space in front of it and expand space behind it. As a result, the ship could travel at many times the speed of light while the ship itself sits in zero gravity, meaning the crew don’t end up as a grease stain on the aft bulkhead from the acceleration.
Unfortunately, the original maths indicated that a torus the size of Jupiter would be needed, and you’d have to turn Jupiter itself into pure energy to power it. Worse, negative energy density violates a lot of physical limits itself and to create it requires forms of matter so exotic that their existence is largely hypothetical.
In recent years, Dr Harold "Sonny" White of NASA’s Johnson Space Center has given the interstellar minded some cause for optimism by showing that even if the warp drive may not be possible, it may be much less impossible than previously thought. White looked at the equations and discovered that making the torus thicker, while reducing the space available for the ship, allowed the size of the torus to be greatly decreased, down to a width of 10 m (30 ft) for a ship traveling ten times the speed of light.
According to White, with such a setup, a ship could reach Alpha Centauri in a little over five months, and oscillating the bubble around the craft reduces the stiffness of spacetime, making it easier to distort. This would reduce the amount of energy required by several orders of magnitude, making it possible to design a craft that, rather than being the size of Jupiter, is smaller than the Voyager 1 probe.
Rademaker’s renderings reflect White’s new calculations. The toruses are thicker and, unlike the famous warp nacelles on Star Trek's Enterprise, their design is the true function of hurling the craft between the stars. Also, the craft, which is divided into command and service modules, fits properly inside the warp bubble, so it won’t be left behind when the captain gives the “engage” command. True, there are some fanciful bits, such as some streamlining, but if you’re going to shell out for an interstellar spacecraft, who wouldn't demand a flight deck with a bit of dash?
So, when will we see this jump off the drawing board and into the final frontier? Certainly not soon, and perhaps never. Right now, White’s ideas can only be tested on special interferometers of the most exacting precision. Worse, the dependence of the warp on negative energy density is a fly the size of a blue whale in the ointment. While it can, under special circumstances, exist at a quantum level, in the classical physical world that our ship must travel through, it cannot exist except as a property of some form of matter so exotic that it can barely be said to be capable of existing in our universe.
Still, it doesn't hurt to dream.
Sources: Mark Rademaker, NASA (PDF) via Io9
