Science in Science-Fiction: Lasers and Death-rays

History of the Death-ray

Almost as long as there has been science-fiction there has been the ray-gun. When silver suited heroes need to stun a bad-guy, or disintegrate a door they are the go to weapon of sci-fi heroes.

Every mad scientist needs one of these.

When science-fiction moved from radio plays and magazines to the cinema the Death-ray, or ray-gun/ atomic disintegrator, moved with them.

Even modern sci-fi still visits the ray-gun (or blaster), but what about the real science behind the beams? It’s a trope that is older than you might think, and while science may now better comprehend these beams, rays and waves, they originally came to us from a time of less sophisticated technology.

Iron Age Heat-rays?

Any fan of Mythbusters can probably guess that I’m going to talk about Archimedes Death/Heat Ray, which alledgedly burned ships during the siege of Syracuse.

An old woodcut illustration doesn’t really do the device justice.

The idea is that by using polished shields,  the sunlight could be reflected and focused on the Roman fleet (who rather handily painted their ships with highly flammable, but waterproof, tar). The bouncing sunlight quickly cooked and ignited the pitch and each boat in turn went up like so much oil-coated kindling. This might have worked, although the Mythbusters twice busted the Myth, they were not targetting a ship designed to maximise ignition, and with all due respect to Adam and Jamie, they aren’t counted amongst the great Philosophers. Of course, a quick perusal of mythology and religious texts that survive from ‘way back’ can also be revealing. But mostly we are talking about the ‘spears of lightning’ that get Alien Astronaut proponents so excited. As for physical evidence, well it might be possible that ancient heat-rays were used in the creation of the UK’s Vitrified Forts, but more likely explanations exist (although not much more likely, they are pretty strange things). So let’s move away from the ancients and look in the place that modern science-fiction really began. He’s an old favourite of these posts

HG Wells ‘Martian Heat-Ray’

HG Wells idea of the heat-ray was in his “War of the Worlds”. The Martians used these devastating weapons to clear onlookers from Horsell Common and destroy artillery and warships.

The return of a science in sci-fi favourite.

Oh, how the scientists of the day scoffed. It is alledged Lord Kelvin himself declared the heat ray impossible as to project the energy, part of the projector would have to be hotter than the surface of the sun, and such a thing was unimaginable. Of course, these days we know that while the Victorian Narrator could only describe it as a heat-ray, we would probably call such a device a Laser (or a Maser if it was tuned in the microwave or milliwave frequencies), and we’ll get to them in a little while. And as for getting hotter than the surface of the sun? A surprising amount of stuff manages that these days, from tokamaks to the inside of pop-tarts. In fact, modern science looking at the sun has discovered that even the space around the sun is hotter than the surface, and we have created laboratory temperatures thousands of times that of the sun’s surface.

Tesla and the Death-ray

According to urban legends, Nikola Tesla (the electrical genius who gave us AC power, the wireless, remote control, the electric motor — and who never drew a diagram until after he had built a device and required one for the patent application), designed an electrical death-ray that could blow planes from the sky, or strike armies over the horizon, but then he was also an ardent believer in numerology and life on Mars (or maybe Jupiter).

The man himself…

According to Tesla himself this weapon, which he called Teleforce was not actually a Death-Ray, because it wasn’t a ray at all, which he understood as a radio beam, or light beam, which could not possibly project enough power as Lord Kelvin pronounced. Instead, Tesla had actually designed a particle (or directed energy) weapon. He describes the weapon having the ability to project intense energy into a very small, even microscopic area over a great distance. Quite how the particles he used didn’t energise the atmosphere between the emitter and the target I have no idea, but Tesla seemed sure that he could, at a range of up to two hundred miles. Tesla certainly could have killed people by earthing his broadcast power, which many believed created artificial lightning. And there are those in the Conspirasphere who believe that the High Atmosphere Aurora Research Project (HAARP) is based on his death-ray design (although it bears closer resemblance to his broadcast power radio system actually), but few rational commentators seem to believe that he ever managed to build it (or his Earthquake machine for that matter), however it is true that upon his death Tesla’s home and workshop were raided by the FBI and his papers confiscated. The seized papers were investigated, and it was announced that there was nothing in them that represented a danger to national security, implying there were no plans for a Death-Ray there, but then Tesla was notorious for not writing stuff down, and would they tell us if the found some anyway?

Buck Rogers, Flash Gordon and Dan Dare

When most people hear the word raygun, what they actually picture is this: During the early to mid 20th century when people thought about science-fiction what they thought about was the rocket ships and ray guns of Buck Rogers, Flash Gordon or if British, Dan Dare. These tales took modern day heroes, fighter pilots and quarterbacks and either took them into the future, out into the stars, or both. It is from these comic books, radio shows and cinema serials that we get the idea of what a raygun should look like. Ming the Mercilless had powerful super weapons that he aimed across the depths of space to attack the Earth, (a trope George Lucas and JJ Abrams are still making bucks from today). But while these weapons had very exciting names, like Atomic Disrupter, or Disintegrator ray, we have very little idea what the exact nature of these vibratory, annhilitory, energy weapons actually consisted of, but they seemed to make short work of hundreds of stunt guys and set of flashes and flash pot explosions throughout their years of sterling service.

The Real Things

So what are the real death-rays? In 1895 the discovery of X-rays probably started science-fiction down this road. These days we know how X-Rays work these days (and how dangerous they are), but when they first discovered they seemed to have a magical ability to peep through solid matter, it ignited the imaginations of fiction writers. For a while rays were the in thing, they could negate gravity, or open hyperspace, or manipulate matter, in short they were science magic.

The Maser and Laser

That all changed in 1953, when engineers and physicists created the first Maser. Technically these days we would call the Maser a Microwave Laser. Named for the acronym, “Microwave Amplification by Stimulated Emission of Radiation” the device emits coherent photons (that means the photons all head in the same direction and have the same phase, they all line up together, unlike in normal light where the photons spread out — or radiate). After the discovery of the Maser it was realised that theoretically other wavelengths of light could be produced in a similar way. Initially these devices were called Optical Masers, but shortly before the first one was created in 1960 researchers decided that a better, more generic name could be created, by using “Light Amplification by Stimulated Emission of Radiation”, the Laser was created.

Moments later this happened in some science fiction authors’ heads

Whether Laser or Maser the device works on a very simply principle that many people are actually familiar with (although they may not know it). Ignore what you know about light, and instead imagine a bath, if you slosh water along the bath (by bending and stretching your legs against the tap end) in time with the water (in harmony or harmonic resonance), pretty soon the water sloshes up completely out of the bath and spills into the floor.

I used to work with lasers, then I got better.

These days lasers are ubiquitous, we use them for everything from communications to cutting steel, but the most powerful lasers aren’t actually visible light at all. Many military lasers are build around Microwave or Infra-red laser technology, mostly because we understand those technologies and have had a long time to perfect them, but the energy densities of such laser weapons are actually quite low, visible lasers can theoretically have much higher power and cause more damage. The goal for military lasers is to increase the energy density by using higher energy frequencies of light. Beyond visible light there are UV lasers, and the energy of every photon increases with the frequency of the lightwave. The higher the frequency, the more damage the laser can do theoretically.

X-ray Lasers and beyond

The American military tried to produce X-ray lasers for the Strategic Defense Initiative (the so-called Starwars program), although it’s doubtful they ever achieved that sort of power. The idea was that the energy levels of the laser beam would fry electronics, boil metals and generally destroy incoming ballistic missile warheads, very (damn) quickly. Beyond X-ray lasers there exist theoretically Gamma-ray lasers. Which, while it cannot create the Hulk, does do about as much damage as old purple pants if the energy densities can be believed. In fact, the projected energy density of a Gamma-ray laser is so great that it would be like harnessing a nuclear explosion everytime one fired, and may be able to sterilize whole continents and countries, and potentially transmute space-time for all we know, if we can ever work out how to build one.

The Gamma-ray laser (or Grazer) represents a number of impossible tasks, one after another. These range from some Gamma-ray mirrors (which since Gamma-rays pass through matter pretty easily will probably be some kind of hyper-dense energy-field contained neutronium) a suitable Gamma-ray pump to get those photons in in the first place (a black-hole could work as a natural example if fed a constant stream of suitable matter, or matter-antimatter annihilation could be used), then the lasing medium itself which would probably have to be quite exotic (perhaps a Bose-Einstein condensate like Positronium, or maybe some as yet undiscovered meta-material).

Although, some doubt that the Gamma Rays would be effective, the rays might just harmlessly pass through most targets, if even one Photon connected the energy imparted could be truly astronomical, blowing apart the molecules, atoms, even the sub-atomic particles, perhaps even the quarks. At those sorts of energies we could expect to see space-time itself warp under the pressure, and might one day lead to Dark Matter and Dark Energy research, but that’s a very long way off.

If you want to find out more about lasers in science-fiction look no further than this awesome post on the subject over at futurewarstories.blogspot.co.uk

Other Directed Energy Weapons

So laser weaponry can be quite limited in what we can achieve yet, but is on its way (to the battlefield in some cases). We’re not just limited to lasers for potential death-rays though. There are other directed Energy weapons (although a lot of them rely on lasers to actually work) .

Some less licensed and more portable than others

Particle beam weapons are in development (which are based on the same ideas as Tesla’s Teleforce) projecting electrons (or similar particles like protons or neutrons) at high-speed and high energy towards a target. These weapons work much like any particle accelerator or cathode ray, accerating and then releasing the particles. They will cause electrical burns and electromagnetic pulses to any matter they hit. Early tests versions are in development that should be able to fry electronics and act as a vehicle inhibitor. Later versions should be able to send small bolts of lightning about the place. 

Plasma projectors may eventually be developed. Which will throw small packets of highly energised (or hot for non-physicists), ionized gas, at their targets. The science is underway, but at the moment we have no way of maintaining the integrity of the plasma packet, so such a weapon would be as dangerous to itself and it’s weilder as to any theoretical target.

There is a theoretical weapon under development called a Pulsed Plasma Projectile, which uses a laser to create a small unstable plasma at the target. The plasma expands burning the target, as well as creating a limited electromagnetic effect that can stun and when tuned correctly induce disorientation.

Clumsy, but effective.

Science-fiction got there first, in this case the Starwars franchise’s Blaster which is sometimes described as using a laser to guide particles to the target and create an explosion there (although it may just be a plasma projector or particle accelerator, according to others).

A better contender for a real life Blaster might be the Electrolaser. It uses a laser to ionise the air to the target and then sends a surge of current down the ionised track of the laser (combining laser waveguides to particle accelerators). Effectively the Electrolaser is a wireless taser, only designed to fry vehicles and missiles rather than people, but I’m sure with enough time a hand-held version will appear.

Possibly the most useful weapon ever

Of course in science-fiction all of these devices are available as settings on the Star Trek franchise’s “Phaser”. In the Trek-verse the Phaser fires a phased Nadion particle stream (whatever Nadions are meant to be; even the Star Trek technical manuals seem to define them only as the particles emitted by phasers). Although early Treknobabble identified them as Phased Lasers. To really create a device like a Phaser we’d probably want some sort of waveguide atmosphere-ionising laser with a choice of particle packets that could be thrown along the beam. Ideally a mix of Electrons and Positrons, Protons or Antiprotons as this would essentially be an anti-matter beam. 

Blooming problems

The problem with all these directed energy weapon systems is called ‘blooming’. Blooming is basically caused because the laser, or particle-beam heats the atmosphere. In fact, if the energy density is greater than one mega joule per cubic centimetre, the atmosphere is essentially cooked into a plasma. The heated plasma then deforms, bends, deflects, or disperses the laser, so that the energy cannot be effectively directed onto the target. These blooming effects get worse with dirt, dust, fog, etc. Meaning that lasers are generally not considered a useful battlefield weapon.

What’s worse is that the surface that is struck by a laser evaporates, or boils off, creating steam and smoke that may effectively block the laser from doing any additional damage. Meaning that lasers are generally not considered a useful battlefield weapon. There’s very little chance that an effective laser pistol will ever be possible, unless some trick of geometry exists to reduce or limit bloom (stuff like Bessel beams seem quite likely).

Blooming will always affect direct energy weapons in an atmosphere, there is no easy science solution to the problem. So while high technology may allow an alien race to generate huge amounts of power in a hand-sized device, tune that to photons of any frequency from Radio to Gamma-Ray levels, attenuate beams to reduce optical spread, diffraction and polarisation issues, there’s no easy way to shoot lasers a long way through smoke and air, with enough power to do damage, but enough control to actually hit a target. Although, I’m sure we’ll get there eventually, but when we do the solution will probably have already negated the need to (like using a force field to create a cylinder of vacuum to the target — if you can do that just cut them with planes of force instead).

Audio Weapon Systems

An odd subset of the death-ray that is potentially under development are the Audio or Sonic weapons (or more often Ultrasonic weapons) they use a mechanical pressure wave to transfer kinetic energy and signal (or a noise as non-physicists call it). Recent developments in AWSs and USWs have seen us able to control sounds in new ways, letting us focus huge amounts of sound into tiny spaces, which can be incredibly powerful and dangerous.

A selection of “Sonic Cannons”

When combined with certain frequencies (and harmonics) it becomes possible to disrupt and interfere with the central nervous system, theoretically even kill with a sound. However, the problems that lasers suffer from are also present in sound, too far from a speaker and the wave is lost, air pressure, wind, weather, and terrain affect these weapons, limiting their range and effectiveness on the battlefield, (where there are other ways of making lots of noise) although they may be more effective for law-enforcement and underwater.

Although this technology is starting to appear, we still have limited ability with these weapons, they are much more likely to deafen than kill, and may just be uncomfortable to be near rather than truly harmful. We just haven’t quite perfected the technology needed to build a “Weirding module” as in Dune, or “Donderkanone” as in my own Ironmaster & Other Tales.

From My Cold, Dead Hands…

So, in conclusion, the Death-ray handgun seems a long way off. But there is no reason not to give alien hover tanks and spaceships laser cannons or plasma throwers, as you like. A few millennia probably separate us from the hover tanks and spaceships anyway.

The biggest problem is power, they require vast amounts of energy to work, and simple kinetic systems are so much easier to build small. We may have some vehicle-busting laser artillery on the battlefield, but we have a long way to go to develop the hand-held phaser. We need a better electrical storage system than batteries, at the very least, and if we’ve got that a lot of other great stuff would be possible as well.

So for the next few decades, at least (and centuries wouldn’t surprise me), we’ll continue to see projectile weapons on the battle-field. If you want to hurt, maim and kill another being, physically striking them is the time-honoured method, and will probably continue that way for a while (although the munitions and guns themselves are probably going to change dramatically as electronic firing and guided bullets become the norm). Hmm… Future post maybe…