Ethan Troy-Barnes separates the fact from the fiction when it comes to laser beams and raygunsThere’s a well-known scene in the first Star Wars movie where Han Solo and another hired gun face off in a bar. The situation is quickly diffused when Han pulls his gun on the unfortunate alien and his expired foe promptly slumps to the floor, leaving the audience unsure over whether they trust this morally ambiguous gunslinger with nothing to lose. Creator George Lucas has since modified the scene to make the infamous bounty hunter come off less cold-blooded, a move resulting in much controversy with die hard fans, as well as endless dollars of profit in the form of merchandise with ‘Han Shot First’ printed on it in shining golden font. The man knows a thing or two about marketing, if nothing else.What is often overlooked in this titbit of movie trivia, however, is the altogether far more farcical means by which Han Solo pulls one over on his bug-eyed adversary. We’re talking about laser guns, folks. Are they really real? And if so, why are we still stuck in the ballistic Stone Age?The answers to all this and more will soon become clear. First of all, we should define what a laser actually is. As any first year science student worth their salt will tell you, the term laser actually derives from an acronym for Light Amplification by Stimulated Emission of Radiation (L.A.S.E.R.). Simply put, this means synchronising a bunch of atoms by exciting them all at the same time. This eventually results in the production of an incredibly co-ordinated emission of photons from all atoms simultaneously, leading to the production of a very intense, very focussed ray of light. By comparison, in a light bulb, photons are emitted at random, producing a low-intensity gleam in all directions.So, lasers are very intense and very precise. This is good; it means they can slice through metal, or judge distances to the moon to within a millimetre of accuracy. It also means they’d make very useful weapons, for a number of reasons. First of all, because the ‘projectile’ is made of pure energy, it therefore moves at the speed of light and would be impossible to evade once fired, even at very great distances. By the same token, it would not produce any recoil or be affected by gravity, making it very accurate. It would also be possible to focus the laser to hit either a very wide or a very narrow target, producing an intensely powerful death ray or reducing the risk of friendly fire, respectively. There is also the potential for near-limitless range, as well the possibility of unlimited ammunition given a sufficient power source.There biggest problem here is the issue of power; lasers are incredibly inefficient and prone to over-heating. So forget Imperial blasters, Federation phasers or Gallifreyan stasers; a low intensity handheld laser gun would at best require a Ghostbuster-style power pack to function, and would probably only fire once before burning out. And that’s without factoring in the plethora of other paraphernalia necessary to make sure the laser works the way it should and doesn’t blow up in your face.Chief among these other things is the issue of ‘blooming’, the phenomenon whereby a single laser beam is so intense that it excites the atmosphere around it and gets dispersed out in all directions, essentially converting our perfectly coordinated beam back into a light bulb and effectively stopping the laser in its tracks. The most practical way to overcome this problem is to mount the laser on a turret with a big mirror which splits up the small, intense beam into a larger, less-intense beam which doesn’t produce blooming, but which gets focussed onto the target with the same intensity as the original beam.In essence, what all of this means is that for a laser to be effectively weaponised it would basically have to be mounted on a static, turret-like fixture and connected to its own dedicated (preferably nuclear) power plant at all times. This would allow for the maximum beam intensity, the minimum cool-down time between consecutive shots and the best chance of nothing going wrong.This ironically concludes that something Death Star would far more feasible than Han Solo’s blaster. In military terms, laser beams would only be practical for use as a defensive countermeasure (e.g. to shoot down incoming missiles in order to protect a location of strategic importance) or as a heavy offensive trump card; for example, to blow up a planet. The Death Star, for example, is essentially a very big laser beam built into its own high-spec power supply and permanently mounted onto a sturdy platform from which to fire. The Emperor knew what he was at, in other words.Now, we all know that laser beams have been around for a while, it’s likely you use them on a daily basis in your DVD player or at a supermarket self-checkout. So why has the military been so slow to snap them up? Well for the reasons outlined above, weaponising the technology has certainly proved difficult. However, recent developments suggest we might be in for a breakthrough soon: just recently German company Rheinmetall Defence revealed a 50kW laser capable of cutting through a steel girder as far as one kilometre away.Additionally, as recent events in the States have demonstrated, we surely don’t need any more lethal weapons in the world. The application of directed energy weapons in the realm of non-lethal weaponry, such as microwave weapons which deter enemies by inducing burning sensations in the skin, is arguably both far more interesting and far more likely to replace the projectile-based firearms that we all know but don’t quite love.