Creating believable worlds is the most essential part of world-building. Gaining an understanding of planet formation for writers is crucial to this process. Writing science fiction and fantasy relies on believable world-building. Readers like to recognize realistic things, even in magical worlds.
So how do you build believable worlds? By starting at the beginning with planet formation for writers. Whether you are crafting an exotic and far away science fiction universe, or a fantasy realm, planets will be at the core of your setting. They are the ground beneath your feet, and how they are created and formed is important for the way they will take shape.
Understanding how planets form gives you a solid foundation for designing worlds that feel authentic.
In this guide to planet formation for writers, you will learn the basics of how planets form. You will also learn about the types of planets you might come across. This will be essential to making your planets not only more plausible but also more engaging for readers.
I. The Basics of Planet Formation for Writers
Before we get too deep into the nitty gritty of world-building, it’s important to understand the science of how planets form. Especially in the context of planet formation for writers. And while we, as humans, still don’t understand everything about how the universe works, we can at least rely on what we know.
Nebular Hypothesis
The nebular hypothesis is the prevailing theory of how stars and planets form. According to this theory, planets begin their lives in a swirling cloud of gas and dust, known as a proto-planetary disk.
For more about nebulas, check out my post about star formation for writers, or check out this article here.
As this cloud of nebula gas rotates around a newly formed star, gravity causes materials to clump together. Eventually, these clumps become small planetesimals.
This is the first step in planet formation for writers, helping you build a solid foundation for your fictional worlds. Think of the nebula as a cosmic nursery, slowly growing planets over billions of years. A million years or a billion years may seem like a long time to humans, but it’s a mere blink of an eye for the universe. And this first stage sets the stage for everything that follows.
As a writer, understanding the planetary nebula can help you envision how different elements and materials might gather on your planet. This composition will influence its geography, climate, and more.
Accretion
After the initial formation of planetesimals, they will begin to collide and stick together. This process is called accretion. Over time, these bodies grow larger, becoming protoplanets. These collisions not only build the planets but also shape their composition and structure. Whether a planet ends up with a rocky surface or a gaseous atmosphere depends on the materials that accrete in its formation.
Understanding accretion is essential in planet formation for writers, as it helps you conceptualize both your world and its cosmic neighbors.
Does your planet have rings of debris that failed to coalesce, like Saturn? Or is it dotted with craters from a long history of impacts, like Mercury? This stage of formation offers creative opportunities for designing the landscape of your worlds.
Differentiation
Once a planet reaches a certain size, the heavier materials sink to the center. This will become the core. Meanwhile, lighter materials will rise to the surface. This process results in a layered planet with a core, mantle, and crust.
For writers, this stage, called differentiation, can influence the geology of your world. Consider our own Earth and its iron and nickel core, and its rocky mantle. And consider how we use those resources in our lives. Planets with metal-rich cores might have advanced mining industries or rare materials crucial to intergalactic trade, while a planet with a volatile mantle could be prone to earthquakes or volcanic eruptions.
II. Types of Planets and Their Characteristics
Now let’s talk about the types of planets that exist, particularly within the realm of planet formation for writers. At least, what we humans know of. Each planet type offers different narrative possibilities, from the inhospitable to the thriving.
Terrestrial Planets
Terrestrial planets are rocky planets with solid surfaces. In our solar system, these include Mercury, Venus, Earth, and Mars. Most of the time, they form closer to their parent stars. This is because lighter gasses that form gas giants cannot accumulate because of the heat of the star. Check out the different types of stars you might find in this article.
But, there is a hypothesis called the Grand Tact theory which explores the possibility that Jupiter may have formed closer to the sun and this may have had a massive effect on the evolution of the rocky inner worlds of our solar system. Read about this hypothesis here.
These planets are characterized by mountains and valleys. They can have active or inactive geology. Venus is a volcanically active world, but has no plate tectonics. Mars is an inactive world, but it has many massive, extinct volcanoes, like Olympus Mons. And Earth is a tectonically active world with plenty of volcanoes.
Because of this potentially active or inactive geology, your terrestrial world can have unique and diverse terrain. This will allow you to craft a complex world with oceans, deserts, forests, or even vast volcanic plains. Writers can explore how their world’s unique terrain and natural resources can shape the cultures and societies living there.
Gas Giants
Aside from terrestrial worlds, there are also gas giants. In our solar system, these include Jupiter and Saturn. These planets can grow massive, sucking up most of their star’s nebula gas during the accretion process. They are composed primarily of hydrogen and helium, and they lack a solid surface.
Gas giants typically have ring systems and tons of moons. Their moons can be diverse. They can be like mini solar systems all on their own. Jupiter alone has 95 known moons!
Each moon your gas world has could provide a rich setting for exploration or colonization in your story.
Including gas giants into your world-building adds grandeur and diversity. They might serve as vital sources of fuel or energy for space faring civilizations. Or their moons could host hidden life forms and human colonies sheltered from the inhospitable planet below.
Ice Giants and Dwarf Planets
Ice giants like Neptune and Uranus are like gas giants but contain a higher proportion of ice compounds like water, ammonia, and methane. These planets are usually far from their stars, making them and their collection of moons frigid and harsh environments.
Dwarf planets, such as Pluto, are smaller celestial bodies that share characteristics with both terrestrial and ice giants. They often exist on the fringes of solar systems and may serve as mysterious, undiscovered frontiers in your stories.
III. Incorporating Planet Formation into World-Building
Now that we’ve covered the basics of planet formation for writers, you have the tools to craft diverse and realistic worlds. But how can you use this information in your stories? Check out my guide to World-building here.
Creating Diverse Worlds
Start by designing a variety of different planets. Pick a few from each category and consider their geology, terrain, and what sort of life may form there. Some might be lush and full of life, while others are barren or extreme in their environmental conditions. This will shape the course of your story by making the planet, the setting, a character all on its own. Does it challenge your character’s existence with hostile conditions? Or does it provide everything society needs to thrive?
Consider how geography influences the development of cultures and technologies. For instance, a mountainous planet with abundant mineral resources may become home to a civilization of skilled engineers and builders. Likewise, a desert planet with scarce water resources might foster nomadic cultures adept at survival.
Climate and Weather Systems
A planet’s formation will also affect its climate and weather. Distance from the star, axial tilt, and atmospheric composition all contribute to the climate. A planet with a thin atmosphere might experience extreme temperature fluctuations, while a planet with a thick atmosphere could be perpetually stormy or covered in clouds.
Writers can use these elements to create dynamic environments that shape the story’s tone and the characters’ daily lives. Harsh climates can force societies to adapt, while temperate climates might allow for flourishing agriculture and peaceful civilizations.
Habitability Factors
When designing a habitable planet, there are a few things to consider. Distance from the star, atmospheric conditions, and availability of water. But remember, not every planet has to be Earth-like. Advanced technology or magic could allow characters to survive on a planet with toxic gasses or extreme temperatures, adding complexity to your world.
Consider again our own neighbors, Mars and Venus. Today they are both desolate, dead worlds. But it’s thought that both had oceans, and maybe even life once. Venus’s location may have led to its demise, while Mars’s small size caused its once molten core to shut down long ago. But imagine turning back the clock a few million years. Maybe we would have seen three vibrant blue green gems in our solar system. And consider that Earth itself has not always been as welcoming as it is now. Its history is one of violence, with a long rap sheet of extinction events. Imagine if humans had evolved during one of these extinction events!
IV. Realistic and Fantastic Elements in Planet Design
Balancing the science of planet formation for writers with creative fantasy and sci-fi allows you to push the boundaries of your world-building journey. There are so many avenues you can take to make your world unique. But how do you blend the science and the magic?
Planet Formation for Writers and Balancing Science and Fantasy
While realism is important, so is impressionism. Grounding your world-building in reality and science while also adding an element of magic and mystery is a balancing art. Don’t be afraid to stretch the science to fit your story. Use real planetary processes as a foundation but add your twist. Maybe your planet orbits a binary star system. What would it be like to see two stars in the sky every night? Learn about different types of stars here.
Consider the long history of our solar system. What if things had happened differently? What would Earth be like, for instance, if the dinosaurs hadn’t been wiped out? Or if we had formed closer or further away from the sun?
Planet formation for writers: Magical and Technological Features
In a fantasy world, you might have planets powered by magical cores or floating cities sustained by enchanted crystals. In science fiction, advanced technologies could terraform entire planets, create artificial atmospheres, or generate energy from black holes. The possibilities are endless, as long as there’s a consistent internal logic to your world.
Planet formation for writers: Cultural and Societal Impact
Planets with unique features naturally lead to unique cultures. For example, a low-gravity planet might give rise to tall, agile inhabitants. High-gravity worlds might produce shorter, sturdier beings. Weather patterns, geography, and resources all influence the way societies develop.
Think about how your planet’s formation might affect the economy, religion, and technology of the people living there. On a stormy planet with frequent lightning strikes, electricity could be viewed as a divine gift, with entire religions or governments built around harnessing this power.
V. Examples and Inspiration from Existing Works
Looking at existing sci-fi and fantasy works can provide inspiration for your own planet designs.
Planet Formation for Writers: Notable Examples
In Frank Herbert’s Dune, the desert planet Arrakis shapes every aspect of the story, from its harsh environment to the spice trade that drives interplanetary politics. Similarly, Star Trek is all about exploring the rich and diverse array of planets that our galaxy offers. Like Vulcan, a desert world in a binary system.
Even on fantasy worlds like Middle Earth, and the world of J. R. R. Tolkien. The entire story took place on or near a tiny part of that world. What else could inhabit the world of Hobbits, Elves, and Dwarves?
Lessons Learned
These works explore how planetary environments influence not only the plot but also the characters and conflicts in the story. By grounding your planets in real science while also allowing for imaginative twists, you can create a setting that feels both fresh and immersive.
Conclusion
Mastering planet formation for writers is the key to creating believable and engaging worlds, whether in science fiction or fantasy settings. Whether you’re writing hard science fiction or epic fantasy, the planet’s story is worth exploring, too. It can influence everything from the climate to the cultures that develop on them. By blending scientific principles with creative freedom, you can craft worlds that captivate your readers and bring your stories to life.
Now it’s your turn! Share your planet-building experiences or ask questions in the comments. Let me know what kinds of worlds exist in your story!
And don’t forget to check out my blogs about Stars for writers, and my guide to world-building.
