"Star Wars" never did let scientific facts get in the way of a good story: Fans just accept that X-wing fighters fly through outer space as if they were jets in an atmosphere, that huge spaceships could float on antigravity drives or zoom faster than light, and that lightsabers cut through virtually everything except another lightsaber (why don't they just make the darn things longer?).
But in the 28 years since the first "Star Wars" movie came out, science and technology have gone in directions that reflect some aspects of that galaxy long ago and far away: Particularly when it comes to space weaponry, robotics and communications, there are increasing parallels between "Star Wars" science fiction and science fact.
That doesn't mean engineers looked to the movies to figure out how to design a modern-day Death Star. Rather, the visions reflected in the movies had an impact on how real-life technologies were presented. The concept for a national missile defense system, which was nicknamed "Star Wars" during the Reagan administration, serves as a prime example.
Final frontier for weaponry
Space warfare was pure fiction when the first "Star Wars" movie came out, but now Pentagon policy is considering scenarios for monitoring missile launches from orbit, shooting down missiles with interceptors, or knocking out enemy targets using ground-based, airborne or space-borne lasers. Just this week, sources in the Bush administration have been talking about taking a more aggressive stance on space weapons.
However, military planners haven't made as much progress on their version of "Star Wars" as they expected to back in the 1980s. In fact, the missile defense system's scope has been scaled back to defend merely against smaller-scale threats from the likes of North Korea, rather than the doomsday scenario of a U.S.-Soviet conflict.
"The expectations have been radically scaled back," defense policy expert John Pike, director of GlobalSecurity.org, told MSNBC.com. "It has achieved a degree of reality that it didn't have 20 years ago, but it has been constrained by reality in a way that it was not 20 years ago."
Slow progress on propulsion
In the field of spacecraft propulsion, researchers haven't yet gotten the faster-than-light hyperdrive to work (even Han Solo sometimes had trouble in that department).
But they have developed distant cousins of the ion drive that "Star Wars" spaceships used for sublight-speed travel. A solar-electric ion drive was used successfully on NASA's Deep Space 1 probe in the late 1990s, and yet another powered the European Space Agency's SMART-1 spacecraft into lunar orbit last year.
The only trouble is, it takes months for these real-life engines to build up a head of steam — so the fusion-powered ion drive on Luke Skywalker's X-wing fighter would leave SMART-1 in the interplanetary dust.
The same drawback applies to space sails, the real-life analogs to the getaway spacecraft that the evil Count Dooku used at the end of "Episode II." Sure, they should work just fine, as the Cosmos 1 solar sail is expected to demonstrate next month. But it would take a long time for a solar sail or even a magnetic sail to reach appreciable speeds.
The upside to space sails is that once they get moving, they should continue moving faster and faster — and that's why Louis Friedman, executive director of the Planetary Society, believes such sails could represent one of the best bets for interstellar travel. Friedman, whose group is one of the backers of the Cosmos 1 project, pointed out that the solar-sail concept originated in Russia in the 1920s and has appeared in science fiction for decades.
"I've always felt that the link between science fiction and science is definitely two-way," Friedman told MSNBC.com. "That's the way it should be."
Then there's the "repulsorlift," the antigravity drive that keeps pod racers and other conveyances hovering over the ground (or, in "Episode III," hovering over the lava pits of Mustafar). Three years ago, NASA spent some money and research time looking for anomalous gravitational effects that, if verified, might have pointed the way to a real-life repulsorlift. But the idea didn't pan out and faded back into the scientific fringe.
Other repulsorlift candidates include the lifter effect, which causes lightweight, highly electrically charged objects to rise into the air, apparently due to a phenomenon known as "ion wind"; and diamagnetic levitation, which can make frogs and other small objects float within magnetic chambers. But for now, these are physics-lab curiosities rather than practical methods for countering gravity.
Robot revolutions
Robotic technology is one of the areas where "Star Wars" really shines: Science-fiction author Nick Sagan, the son of the late astronomer Carl Sagan, recalled how he and his father quibbled over the first movie's scientific slips. But he also paid tribute to the way "Star Wars" portrayed the various breeds of robots.
Sagan said the assorted shapes and sizes of "Star Wars" robots — some suited for industrial purposes, others for service or entertainment — helped blaze a trail for contemporary machines that will vacuum your carpet or serve as a sassy, pint-sized companion. "The goofy commercial robots owe a lot of their visual design to the 'Star Wars' robots," Sagan said.
Meanwhile, the movie saga's central character, Darth Vader, was a walking advertisement for body-part replacements, if not the ideals of the Jedi order. Real-life prosthetic limbs are starting to take advantage of advances in neuroscience and engineering, to catch up with the vision sketched out in the "Star Wars" movies.
3-D is your destiny
"Star Wars" has also been ahead of the curve in communication technology. The most common medium in the movies is the 3-D interactive display — for example, the holographic message projected by R2-D2 at the beginning of the original movie, or the interactive star map manipulated by Obi-Wan Kenobi at the Jedi Archives in "Episode II," or the virtual telepresence of Jedi knights at the council meetings in "Episode III."
The same kind of displays can be seen nowadays in other sci-fi movies such as "Minority Report." But could they really work the way they do in the movies?
Yes, but it's not as simple as "Star Wars" makes it out to be: You might have to look into some sort of holographic screen, or use virtual-reality headsets and haptic gloves. Virtual-reality 3-D technology is actually old hat: Several years ago, engineers used VR to work on virtual prototypes for the U.S. military's Joint Strike Fighter before the plane was even built.
Another method would be to turn the air itself into a display screen: That's what the Finnish company FogScreen has done with its "dry fog" video projection device. Illinois-based IO2Technology has developed an even more mysterious contraption called the Heliodisplay, which projects interactive imagery onto "modified air."
Such 3-D, virtual-reality experiences are quickly catching up with science fiction, Sagan said.
"I would argue that multiuser videoconferencing looks a little sharper than that hologram," he joked. "Of course, it would have been less dramatic if R2-D2 suddenly popped out three headsets to watch the hologram."
In a final twist, the technology will soon be turned on "Star Wars" itself: The next step for the movie franchise is a digital conversion of all the films to 3-D format, starting in 2007. So when you watch the hologram of Princess Leia telling Obi-Wan Kenobi, "you're my only hope" ... you'll actually get the hologram's 3-D effect for the first time.
Thanks to Jiun-Tyug Chern for updated information on midair displays.