In addition to self-driving cars and humanoid robots, it seems we can now add one more science fiction device to the world of reality: laser guns.
While not as peaceful or significant as developing a flying car or faster-than-light travel, laser guns still represent a significant achievement of science, along with many sci-fi nerds' dreams come true. Long the weapon of choice in novels about aliens, robots, space travel or some combination of the three, few weapons could be more lethal than a laser gun. Push a button and a beam of light capable of destroying almost anything comes out; how elegant (despite the opinion of Obi-Wan Kenobi). Of course, we're not quite there yet.
Zeus, the laser gun developed by the U.S. Army to detonate roadside bombs, may represent the first step toward this aspect of a typical sci-fi future. It is a directed-energy weapon"" (to use the military's term) that actually uses a laser beam to detonate its targets.
It's not exactly a hand-held device, since the beam director, operator's station, support subsystems and the laser itself are stored on the back of an unarmored Humvee, according to a 2002 story of its development in Military & Aerospace Electronics. But, ungainly as it may be now, the fact remains that we now can count lasers among our military arsenal.
""If one knows where [roadside bombs] are located with the precision required for a (presumably) focused laser beam to be effective,"" wrote a laser expert in an e-mail, ""destroying them could probably be achieved by any of a number of methods."" And in fact, the science behind a machine like Zeus is fairly straightforward.
""There is nothing magic about radiation from a laser,"" wrote William Bridges, Caltech Carl F. Braun Professor of Engineering Emeritus, in an E-mail. ""The radiation is absorbed by the target and [it] heats up, hopefully exploding the target. You need to deliver a certain quantity of energy to raise the temperature to the ignition point.""
Exactly how much energy that is depends on experience with the specific materials. Since energy is just power times time on the target, this will likely require many kilowatts times many seconds, resulting in many kilojoules (kJ) of energy, he said.
Bridges also noted that even the best, most advanced lasers have pretty poor efficiency, usually less than 10 percent; this means that to deliver one kJ of energy to a target, the laser must safely get rid of the excess nine kJ it spent delivering the energy.
""Personally, I think a rocket-launched grenade is a much cheaper, more effective way of delivering a lot of energy to a small stationary target to blow it up,"" wrote Bridges. ""The missile delivers most of the energy to the target, while the laser dumps most of the energy in YOUR airplane!""
While Zeus is designed to be a non-lethal defensive laser, that won't always be the case.
Just two months ago Northrop Grumman announced the introduction of its FIRESTRIKE laser, which its press release called ""a ruggedized, high-energy, solid-state laser designed as a line replaceable unit (LRU) for battlefield applications, ready for order now."" Like those Bounty Select-a-Size paper towels, which allow one to choose just how much paper towel to use, so can the LRUs be combined to fit ""specific warfighting missions and/or platforms,"" according to its brochure. ""The result is a flexible, 'game-changing' military capability with tailored lethality.""
Although it shouldn't be surprising that a defense contractor would use the latest technology to build a better weapon, the clearly lethal intention for the FIRESTRIKE laser may give some pause. Is it possible this is leading up to the first actual hand-held laser gun?
Professor Bridges thought it unlikely, owing to the complicated machinery necessary to safely get rid of all the laser's excess energy, and referred to a drawing he used to show in lectures. ""It showed a stick figure holding a pistol-like device, but there were cables dangling out of the handle that went over to a large tractor-like vehicle with a huge electrical generator, and a huge fan-and-radiator cooling system,"" Bridges wrote. ""Not exactly what Buck [Rogers] used.""
Still, given the remarkable ability of science to miniaturize and surprise, it might be prudent to ask what implications the possibility of such a hand-held device might have. Lester H. Hunt, a UW-Madison philosophy professor who studies guns and violence, thinks it wouldn't really be a big deal.
""I don't see any reason why [laser guns] would present a different issue than standard metal slug weapons,"" Hunt said. ""The technology isn't necessarily raising new issues,"" assuming the it has no unforeseen effects, such as a laser beam going right through everything in its path or interacting unexpectedly with peoples' physiology.
So what does all this mean? First, it means that the use of military lasers is on the rise, which probably won't affect the majority of the U.S. population.
Second, it means that even though it's possible that someday hand-held laser weapons might become reality, it's a small possibility, and probably wouldn't change much anyway.
Third, and perhaps most tragically, it means we'll have to wait that much longer for flying cars and faster than light travel. But, given their obvious military advantages, perhaps it's only a matter of time until these become reality too.
