Fudges – Laserswords (discussion).

Back in December, I left a poser with my reviewers team about fudges used in Science Fiction.

What are fudges? Nothing to do with confectionary. It’s where known science is wobbled in a consistent way to allow some scientific rule or technology to work, usually under the possibility that it might one day happen. Most SF material has at least one fudge in any of its mediums. Generally speaking, the most well known are time travel and faster-than-light space travel but there are many others. Under normal Science Fiction Convention, these fudges have to be consistent and wide-spread throughout a reality and not a get away with it card because the author wrote him or herself into a corner.

What follows below is a discussion between myself and Neale Monks regarding laserswords or as popularised in a galaxy, far, far away, lightsabers. As it was conducted over several emails, I’ve kept in the greetings and such so you can see how the discussion progressed.

If you want to pass comment, there’s the reply box at the bottom of this feature. If you want to discuss a particular fudge, then contact me in the usual way off the email at the end of the editorial. We can then either do a similar parley discussion here or an article.


Hello Geoff,

The use of lasers, surely…

Light sabres where the laser beam stops a few feet from the source!

Laser beams that visible extend across the field of view from the attacker to the victim! Visible light laser beams that aren’t reflected from shiny surfaces!

This latter was actually discussed in the ‘Dune Encyclopaedia’ where the (in-universe) commentator described how early laser beam weapons bounced off reflective surfaces with unfortunate effects for the attacker in particular. So within the ‘Dune’ universe and uniquely I think in Science Fiction, laser guns (‘lasguns’) use non-visible wavelengths of light such as UV that did not reflect as easily and weren’t diffracted by the atmosphere.

Cheers, Neale


Morning Neale

I’m going to have to have a think on this one for the final piece but if memory serves, I think it is possible to give a light beam a limited length but it would be based off its wavelength and how much power is charged into it. Look at ruby laser lights used for treating eyes. If they didn’t have finite length, you would be getting a lobotomy at the same time.




Sticking my hat on as a physics teacher…

A laser beam can be thought of as a single beam of light at a specific wavelength. All the waves have their peaks and troughs at the same time, ie are in phase, a property that is called coherence. In air, visible light laser beams get scattered by particles in the air, so without sufficient power, they gradually peter out because they stop being coherent. That’s why a pen laser doesn’t go all the way to the Moon. The lasers they point at the Moon to measure distance are very much more powerful (gigawatts versus milliwatts).

Ordinary lasers don’t actually have a huge amount of power. Just yesterday we (the teachers) were pointing a new laser at our hands to see if we could feel the warmth. Some of us could, some of us couldn’t. The colour of the laser makes a big difference, too. Blue light has more energy than red light and since red objects (like blood) reflect red light, a red laser largely bounces off blood, whereas blue lasers are absorbed by blood, which makes it heat up, and so cauterises small cuts. I’m not sure the details on eye surgery, but a quick look on Wikipedia suggests UV lasers are used. UV light is readily absorbed by cells causing them to heat up. But by definition, if it’s absorbed by something, it won’t go beyond that something, assuming the power of the laser is tuned to be just enough to heat the cells it hits but not be enough to burn right through them.

Does this make sense?



Evening Neale

Now you hit the nail or light on the head. Not enough power. When you have realities like ‘Star Wars’ and ‘Dune’ when they have unlimited power for faster-than-light travel, having a miniature power source to boost the power of a laser is a minor task.

So, is a light or laser-sabre totally impossible or a fudge?? The only real problem is power and limiting the length but even that can be done with modulation. That doesn’t make it impossible he says as a devil’s advocate.



Hello Geoff

If you supposed a light sabre was actually plasma rather than light, a magnetic field could force it (no pun intended) into a discrete blade. That might allow for some interesting interactions I suppose when the blades of two light sabres hit each other. I think someone wrote a ‘Science Of Star Wars’ book but I haven’t read it. Have you?

A true laser beam light sabre doesn’t really make any sense at all scientifically. At least, not from our current level of understanding. Light rays travel until absorbed, though they can of course be bent in various ways (glass lenses for example, but also extremely massive objects such as black holes and galaxies).

Cheers, Neale


Still me

According to Amazon, there was a ‘Science Of Star Wars’ back in 1998 www.amazon.co.uk/Science-Star-Wars-Astrophysicists-Independent/dp/0312263872/ref=sr_1_1?s=books&ie=UTF8&qid=1418500190&sr=1-1&keywords=science+of+star+wars    but the interiors don’t show those pages and things would have moved on in the past 16 years anyway.

I remember the original blueprints depicting a crystal modulator at the top of the stick. Just because it’s called a light device doesn’t mean it’s purely light. More to the point, why have a weapon like that when there are blasters available?? Where ‘Star Wars’ is concerned, it’s probably an old weapon that affirms their knight status.

OK, so it’s a limited size plasma weapon. Is it still that impossible?? It’s really energy base out be a limited length and any beam beyond that wouldn’t be visible or harmful. Mind you, the device isn’t left on for long.



Hello Geoff

No, not impossible. Plasma is the stuff inside those plasma globes as well as fluorescent tubes. To be sure those use glass to trap the plasma inside an inert gas, but scientists use magnetic ‘bottles’ to trap plasma (though not very efficiently) and it isn’t a big deal to imagine an advanced tech being able to create perfect magnetic bottles on the go using handheld devices.

Cheers, Neale


Still me

Well, you did suggest plasma as an alternative and the only problem here is containment. Essentially, light-sabre weapons do give off a distinctive hum which would tend to suggest some sort of magnetic containment field in operation. The fact that when two of these are opposing each other in battle, why can’t one cut through the other. With a magnetic field, they literally would bounce off each other.

If anything, none of the problems aren’t solvable, if we have technology so not really a fudging. Whether we would let people walk around with such weapons is debatable. Considering the ‘Star Wars’ universe also has advanced cyborg replacement technology available, it seems this was addressed a long time ago.



Morning, Geoff!

I believe Clarke said something along the lines of, ‘If a scientist says something is possible, he is very probably right; if he says something is impossible, he is almost certainly wrong.

Cheers, Neale


Still me

Clarke liked to edge his bets.



So, two different viewpoints. Looking objectively at the discussion, if someone was to take what we can currently do with lasers up many notches with a decent power source, a lightsabre could be possible but have limited applications depending on what colour setting jewel you pass it through. But would you really want to use one when you could quite easily burn off your own fingers and limbs?

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