Science fiction, being based in science, shows us humanity and the universe as it could be. Whether we’re considering the effects of advancing technology, ways scientific discoveries impact our lives, and even how both can modify the human condition, sci-fi helps us look at what our real world might become before the future arrives. But let’s acknowledge that there are some things commonly seen across science fiction that are unrealistic, impracticable, or downright impossible.
The laser blaster or plasma gun, and all their variants, appear frequently in sci-fi as futuristic and flashy substitutes for modern firearms. But the way such energy weapons work is wholly impractical and unrealistic.
The Basic Premise: Blasters are energy guns that replace bullets and deadly gunshot wounds with flashy and non-horrifying ways to incapacitate targets … all of which is nonsense.
Let’s Be Realistic
Often a show, video game, or movie wants to show its audience that the story takes place in the future, one of technological advancement. An obvious and often-times familiar way to establish this is to have guns fire obvious beams or bolts of glowing light instead of shooting bullets. This, of course, serves several functions besides communicating the advancement of weapons technology in the setting. Often times the lasers are color-coded, with bad-guy lasers being red, and good-guy lasers being green or sometimes blue, so the audience can tell who is winning easily. Blasters also frequently show their shots as being slow, and thus easy for the heroes to safely dodge, and also causing minimal injury – often a character will be hit in the shoulder, but even if struck full-on in the torso the worst they’ll experience is to get knocked down and for their clothes to be scorched. Because of this, the blaster or laser gun is an ideal substitute for handguns and assault rifles in children’s TV programming (as anyone who grew up watching 1980’s cartoons can attest to): showing realistic gun violence in any positive light teaches children that such violence is okay, the argument goes, but by using unrealistic lasers the action scenes qualify as the much tamer fantasy violence.
And unrealistic it is indeed.
For starters, we’ll consider lasers. A common laser (originally an acronym for light amplification by stimulated emission of radiation) would simply shine a focused beam of light on a target, like a flashlight with no scattering. This beam is invisible, and, being light, would travel at light speed, nearly 300,000 km per second. At typical fire-fight distances of 30 to 50 meters, this would mean the dot of light lands instantaneously, and it essentially cannot be dodged. Everyday lasers would not usually cause burns and gunshot wounds, but even civilians in many places can purchase lasers that are strong enough to very quickly cause blindness.
Permanent blindness, at that.
If inflicting life-long disability on your enemies isn’t your thing, though, you’re going to have to increase the power. By a lot. The greater the energy output for your laser, the more it can cause injuries like what a gun does, but this also comes with the need to have higher energy capacity in terms of batteries, which are usually electrochemical. Because of the way that such energy is stored, instability increases with capacity, meaning that for a laser powerful enough to compete (or out-compete) with firearms you are essentially siphoning off the power of a potential electrochemical grenade. (Check the Atomic Rockets link for more details.)
Since you’re dealing with light, one of the other effects that firing the beam has is that, in an atmosphere, EM radiation will scatter. Think of a billiards table full of balls bouncing every which way all the time: when you go to shoot a stream of them into that chaos, some are going to scatter rather than going through, and some will bounce back towards the direction of fire. In this analogy the billiard balls represent both air molecules and photons of EM radiation – which in both frequency and power are strong enough to be damaging (which is why you are using it as a weapon), now hitting you with backscatter. The person firing the weapon is likewise hurt by it.
If instead the shot is plasma, electricity, or other kinds of energy, the weapon becomes more complicated still. At stupidly high levels, one could achieve one of the most fabulous feats of sci-fi blasters: disintegration. This is a handy plot device in shows, as it’s a great way to cleanly dispose of a body for stealth purposes, or for intimidation. And such a threat would be very real, for the energy pack such a person would need to carry is monstrous. To accomplish the goal of turning a human being (made of water but also solids like carbon and calcium) into steam and plasma, the energy requirements are so severe that they would essentially be carrying a building-wrecking explosive.
One that could go off catastrophically if damaged by a lucky shot or if suffering a malfunction, killing everyone, including the carrier. This is beside that fact that, even when used properly, the victim does not cleanly just disappear, since a stupid amount of heat energy gets involved.
In the end, the blaster is trying to simply repaint the gunslinger or soldier’s weaponry into a sci-fi aesthetic, while completely disregarding the mechanics of directed energy weapons and the various complications that would be inherent to the technology. Blasters demonstrate a disdain for considering the practical limitations of such tech, wholly in favor of making showy gunfights that grab the attention and work in service to the author’s convenience and style, while disregarding a basic check of any facts about the technology.
“They have a gun,” the writer says.
“But this is sci-fi,” the genre replies.
“So stick the term ‘laser’ on the front end, and now they have a laser gun,” the answer comes back, without another moment of thought. And we, as the habituated audience, have grown up accepting it.
The Bad: Why You Can’t Have It
Blasters make no sense for the reasons already outlined above. The power consumption and dangerous storage necessary, the inability for our intrepid heroes to dodge any attacks, the fact that lasers are often invisible to the characters and audience, that lasers blind rather than blast, and the real risk of backscattering all make the firearm a far more reliable and less complicated means of attack. But there is a deeper problem here.
Conflict drives narratives, but often it seems that it is the escalation to violence that gets viewers. It shows the characters obviously doing something, and something dramatic at that. This perpetuates a kind of gun culture, whether romanticized or not, and while it has been exported to markets around the world, such media has a strong origin in the United States. At the time of writing and hearing about the latest mass shooting du jour, it prompts one to wonder what drives, and perpetuates, the cultural fascination with firearms. Does our media really require a reliance on gun action, even in the supposedly toned-down version that is the laser light show of a sci-fi fight that qualifies as fantasy violence? Even Star Trek, which sought to depict a utopia-like society in space, still relied on weekly phaser and photon torpedo battles to entertain its audiences in between plots about people. I’m not saying, for any personal or moral reasons, that you can’t have media with violence in it – but I think the question of, “Does the inclusion of these gunfights add anything positive, or perhaps instead add something negative?” has validity.
The Good: Why You Still Want It Anyway
All that said, gunfights are a part of the cultural landscape in movies, TV shows and video games, in and out of sci-fi. And to have cool laser shootouts is entertaining. Beyond scientific accuracy and beyond moral responsibility, sometimes what you want to see is a conflict between characters or factions that has reached it’s ultimate conclusion, each side hammering down with a barrage of brilliant blaster-fire, colors and sparks flying every-which way. It can feel elevated above a modern gunfight, with high technology presenting high-stakes situations. It’s not just a celebration of the sharpshooter, but of anyone who can pick up a weapon that works to defend themselves from the world they’re in and the threats they face – and some iconic advanced technology can be seen reflected in all of those things. The blaster gives us what we want, or at least what we’ve come to want, regardless of whether it’s realistic or not.
And the Weird: If You Still Really Wanted To, Here’s What You Could Do
So despite all the problems outlined above, you still don’t want your heroes to trade in their nonsensical plasma revolver for an old-fashioned modern pistol, and still keep to realism? Well then, consider either working around the issues or adapting to them.
Lasers move at light speed. This makes them excellent for space battles! Rather than launching missiles between very distant spacecraft or firing bullets at enemy astronauts, laser weaponry moves at light speed and has no risk of backscattering in a vacuum. Plus, lasers have no recoil, so a fired shot won’t put you off-kilter. (Just don’t forget: In space no one can hear you go, “Pew, pew, pew”.)
Speaking of backscattering, you could include a radiation deflector into the barrel of the gun, or have a radiation reflecting shield that protects the wielder; many older designs of pulp ray guns incorporated these.
Rather than relying on lasers, consider directed energy weapons that deter in non-lethal ways rather than kill. Lasers can cause permanent blindness, but could cause temporary blindness instead if toned down and adjusted (plus that opens the door for replacement cybernetic eyes in your story). Thermal weapons can deter by exposing people to intense off-putting radiation that compels those who feel the heat to move away. Sound weapons can also deter, through either loudness or pitch.
A gun with an external power-cable allows the blaster to scale up, becoming a turret or vehicle-mounted artillery piece; some military companies have experimented with these technologies in the real world. Although most such prototypes rarely go beyond niche applications, there’s no reason in physics that you cannot have blasters in your setting by one contrivance or another.
The blaster, laser pistol, and plasma gun, as with many other kinds of energy projectile weapons, are iconic, flashy and classical parts of the science fiction arsenal. But they come with problems that make conventional firearms a more rational option for nearly any hero or villain to wield instead. All it takes is a little pause to think, and some scientific background knowledge, to recognize that they make little sense. Choosing to avoid such an unrealistic fantasy and instead selecting the more plausible alternatives is one of the cornerstones of credible science fiction.