Sometimes I run across an older book that’s usually out-of-print, but has exceptional wisdom locked up in its pages. I found this one at my local Half Priced Books.

The very nature of this book—20 essays about writing by the best SFF authors—makes it hard to review as a whole. I think a better strategy is to look at each chapter in detail.

See all of my WSF&F chapter reviews.

Chapter 10: The Creation of Imaginary Worlds

This chapter by Poul Anderson is subtitled The World Builder’s Handbook and Pocket Companion. After reading this chapter, I can say it truly earns its name. Unlike the previous chapters, it doesn’t discuss the mechanics of writing or storytelling. It is focused on one thing: building a planet for a story.

Anderson opens with a bit of science fiction history, and recognizes that the type of story with a highly detailed extraterrestrial descriptions is definitely a sub-genre. But when that’s the nature of the story, it should be done well.

However, when a story does take its characters beyond Earth [the reader] is entitled to more than what [they] often get. This is either a world exactly our own except for having neither geography nor history, or else it is an unbelievable mishmash witch merely shows us that still another writer couldn’t be bothered to do [their] homework.¹

He gives an example of what he considers a poor job of world building: “a world that is nothing but sterile desert, devoid of plant life, yet has animals and air that [humans] can breath.” By pointing out a world building faux pas in a beloved franchise, he inadvertently points out that an epic story can gloss over those flaws. But the corollary is also true. A well-developed world can become the story, but only in the hands of writer with the proper scientific background.

But as always, the middle ground is most fertile. With a grasp of basic science and grade school math, a writer can build a believable exoplanet. He says it requires imagination and a willingness to work. But by “work” he means “fascinating—sheer fun.”

This is the jumping off point for the rest of the chapter. Anderson focuses his explanations towards building a planet on which humans can live without the need for excessive life support systems. He uses a planet he designed, Cleopatra, as an example of the process.

What follows is a process that starts with a star, and ends with a believable planet. I’ll attempt to summarize the basic steps, but anyone interested in the details should read the original.²

It all begins with a star. Without one, there would be no planet formation.³ There are many variables to consider when building a star that your characters will see.

• The class of a star, or where it lies on the spectrographic scale. This ranges from blue giant to red dwarf.
• Its class will have a direct effect on its lifespan. The hottest blue giant live fast and die young in a supernova. The chance of planets forming around them is slim.
• The class will also be an indication of its, color, mass and radiation output. The cooler end of the spectrum lends itself to planet formation.
• The location of the star in the universe, possibly in relation to Earth. Where the writer hangs the star will effect story logistics and if nothing else, the characters’ view of the night sky.

Using this information the writer can choose the type of star, and then begin to hang a planet in its orbit. Everything about the basic composition of the planet depends of the nature of the star.

• Temperature
• Radiation received
• Orbital distance and path
• Length of year
• Shadows (angularity and edge)

The work isn’t done yet, but becomes easier now the basic astronomy is done. The planet will have its own personality with things such as:

• Gravity
• Atmosphere
• Elements present
• Topography
• Tectonic activity
• Rotational speed
• Presence of moons or other satellites
• Tidal activity
• Axial tilt
• Weather patterns
• Seasonal patterns

Each item will effect other items, and then have a corresponding effect on the flora and fauna that call the planet home.

This chapter focuses on the details while delving into their scientific origins. It’s a lot to take in. But Anderson’s advice remains: if the writer “has given some thought and, yes, some love to the setting, that will show in the words.”

1. I’ve changed the gender specificity of this because it’s not just men that read and write science fiction. ↩
2. Used copies of the book are available, and the essay might have found life elsewhere. Google exists, you’re on your own. ↩
3. Many stories can have planets without stars. We saw that in the last chapter. But the star is needed to for the planet to form. ↩