Introduction
I was thinking about the next step in building my world and landed on physics. I wondered how it’s laws govern reality. At one point I asked myself: what if the laws of physics were different? What if they worked differently, or didn’t work at all?
I started digging into this field of science and quickly realized the topic is a serious challenge. In this article I’ll describe my experience and thoughts about physics in a fictional world.
I focused on physics because it defines the rules that govern reality. I understand physics, in the context of a fictional world, as the most basic determinant of what is possible and what isn’t. I don’t yet know exactly how my world will look. I am, however, certain that the choices I make regarding physical laws will affect everything else. The sooner I address them, the better.
I revisited school lessons and re-studied the laws and principles of physics. I wondered what would happen if physics were completely different. As I learned more, I soon realized that the world could become utterly unrecognizable even after modifying relatively simple rules.
Action and Reaction
Take Newton’s third law of motion as an example.
Newton’s third law — the law of action and reaction — states that for every action there is an equal and opposite reaction. These are two forces that always occur in pairs. In everyday life this means, for example:
- when you row, the oar pushes water backward and the water pushes the boat forward;
- when a soldier pulls a trigger, the bullet is expelled from the barrel and the shooter feels the recoil;
- pushing a shopping cart: you push the cart forward, and the cart pushes back on your hands (you feel resistance);
- even walking: the foot pushes the ground backward (action), the ground pushes the foot forward (reaction), and that’s how you move — something so obvious we rarely think about it.
What would happen if this law was modified?
Suppose the reaction did not occur. At first I thought firearms would have no recoil. Sounds intriguing — I started wondering how a typical battlefield would look and whether this would affect soldiers’ accuracy. Transportation could also be completely different, since it might become possible to create drives that require no fuel. I became worried, however, when I considered gravity. If reaction forces didn’t occur, a person could hypothetically push off the Earth’s surface and fly into space — not a pleasant prospect.
The Earth itself would stop orbiting the Sun, because attraction would no longer function; it would simply fly straight into space.
One such change in the rules of physics could have enormous and catastrophic consequences for life.
This example vividly showed me how important physical laws are. It’s just one law, but changing or removing it would radically transform life on Earth. I suppose you can invent your own physics in a fictional world, but properly representing those new realities would require far more knowledge than I currently possess. It would be a challenge I might not be able to meet.
Therefore, the world I’m creating won’t be particularly unique in terms of the physical laws that govern reality. That doesn’t discourage me — it made me aware of how physics defines what we consider believable, especially in narrative.
Physics in Narrative
I understand it this way: we call something believable if, in our judgment, it is probable — it has a real chance of happening. What physics allows is what we tend to accept as possible.
For example: if someone tells me about a person walking down a street, I’ll believe that could happen. If someone claims they saw a person push off the Earth with their legs and fly into space, I would be skeptical. Reading such a scene in a book would make me immediately think: that’s magic, or a dream, or a piece of science fiction where the physics permits such phenomena.
Of course, a person flying off the ground is an extreme example. For another example, the same principles apply when describing combat scenes. I wouldn’t expect someone facing a hail of a hundred arrows to deflect them all with a sword or catch them mid-air — unless they have supernatural abilities. I will, however, believe that a person might dodge a single arrow with a bit of luck. It’s different if the character has magic, superhuman reaction time, or the arrows themselves travel much more slowly.
I want to build a world that resembles ours — even the smallest change to the foundations of physics could make it unrecognizable. For that reason I will stick to “Earth-like” physical laws. I won’t invent new ones or change existing laws; I’ll leave that to specialists. I will operate according to the laws that govern our reality. The one possible exception is magic, which — in the future — might bend or even break those laws, but that’s a discussion for much later.
Conclusion
Creating a fictional world requires knowledge from many fields. I have no doubt that some of them are major challenges. I know I won’t invent entirely new laws of nature — I won’t, for example, devise my own three laws of motion. Still, by studying physics I’ve learned interesting things, gained a clearer sense of what I consider realistic, and better understood my own limitations. Ultimately I’m glad I decided to create a fantasy world similar to our Earth — though who knows, maybe one day I’ll build something completely different.
How about you? How deeply do you delve into physics and the laws that govern reality when you create your world?