I write Science Fiction. I also write Fantasy. And they are two very different beasts in some respects. Not that you would notice it on TV or in the movies, where they are treated as one anything goes genre, with interchangeable tropes. Take the trope of Shape Shifting. Beings change shape at will, or add and subtract mass, the same whether it is explained by supernatural or biological effects. I will go over some of my own pet peeves below. But in my opinion science fiction should at least follow some of the laws of science. Unless you are discussing technology like in Michael Moorcock’s Dancers at the End of Time, in which tech has evolved to the point where it might as well be magic, and matter and energy can be changed back and forth at will. But most scifi is set in the not so distant future, and should follow the basic rules. So let’s get on with home of the things that offend my sense of the real, and interfere with my ability to suspend disbelief.
1. So Is That a Tentacle You’re Hiding, or Are You Just Glad to See Me? Was watching The Thing the other day. Great movie. Love it. But what a bunch of crap. A creature that looks like a human transforms into a tentacled monstrosity before your eyes. Biological systems don’t work at
this speed. Leg bones and joints don’t just spring into existence within seconds. Not in natural systems. Maybe in supernatural systems, but we’re talking the Thing From Another World, not the Wizard from another World. Now it would be different if those extremities were hidden until needed. But no, they spring into existence from other structures and organs. In another movie I recently saw some machine could change the genes of the victim, and a human went from normal to a mass of tentacles in an instant. Sorry, but it wouldn’t happen that fast, if at all. The change, if it occurred and wasn’t fatal, would happen slowly as new proteins were produced by the new DNA. Cronenberg got it right in his version of The Fly. Seth Brindlle changes into the fly a little bit at a time. The third aspect of this is how alien life forms seem to grow rapidly with no input of mass. Remember the movie Species? A test tube is opened in a closed room and suddenly there are tentacles everywhere (these movie makers seem to love tentacles). Nothing in the room but air, and the biological constructs spring into existence made out of proteins made out of what?
2. Let’s Just Coast to a Stop. Isn’t it wonderful how spaceships can just turn off the engines and coast to a stop. Just like a car going up a hill. Only one little problem. It doesn’t work like that. You see, there is no air resistance in space, mostly because there is no air. If a space ship
turns off its engines it will just drift at the current velocity in the current direction forever, unless some other force acts upon it. They don’t slow to a stop like a ship in the water. Another aspect of this is the depiction of fighter craft in space. They bank and twirl and do everything you would expect to see an Me109 perform during the Battle of Britain. Unfortunately, these maneuvers only work in atmosphere. The third problem in most science fiction is the depiction of spaceship deceleration. They boost along for hours or days, and then slow to a stop with a quick burn. Here’s the problem. If you accelerate for a certain amount of time at a certain rate you need to decelerate with the same amount of time and/or energy to stop. It makes you plan your trajectory in advance. If you don’t want to slam into something at the end you either need to do a sensible deceleration, or plan on something that might plaster the crew to the walls like a jam.
3. Where’s the Earth Shattering Kaboom? Many movies depict weapons of the future as almost impossibly powerful. They can in reality be devastatingly destructive, but probably not to the degree depicted. An example of this was the Death Star of Star Wars fame. With a millisecond flash of energy the station blasts an Earth size planet to bits. It looks awesome. And it will be possible to make weapons that can render a planet lifeless. But to destroy it completely? I read an article some years ago, it’s probably still on the net somewhere, where a physics student calculated how much energy would be needed to destroy the Earth. He came up with the figure of half the energy production of the Sun over a year. Doesn’t seem possible that something as small as the Death Star could generate that kind of energy. The other problem that most TV and movies don’t address is the waste heat. To generate terawattts or petawatts of takes an enormous generating system, unless you are taking energy from the zero point. Even at almost perfect efficiency there would be gobs of waste heat. But ships in movie or TV scifi don’t ever seem to have a problem with overheating.
There are many great examples of using the science right in great scifi literature. Not so much in movies and TV. Still love them, but I don’t consider them good examples.