Having a variety of human-inhabited worlds is one of the plot-friendly aspects of many science fiction settings. Authors may find themselves confused about how to provide colonists with the means to reach distant worlds while avoiding trade-driven homogenization that might inhibit planetary cultures from developing in a plot-friendly direction. But don’t worry! There are many ways to give the world enough space to find its own destiny.

In fact, there are at least five.

One solution is to have someone else (or something) provide the means by which humans spread from one system to another. If humans could not control (or even understand) the way people traveled from one system to another, everyday contact might not be possible. Clifford Simak’s “Chosen of the Gods” tells this in its backstory. The vast majority of humans (except for a few humans and a group of robots) have been taken from Earth by some unknown agency. Thousands of years later, after considerable cultural differences, recontact occurred. Alison Sinclair’s Cavalcade shows the beginning of a similar process. A mysterious starship offers the opportunity to leave the solar system, and many people board the ship, only to realize the consequences of isolation later.

Some environments offer enough human technology to bridge the gap between the stars through extraordinary efforts, but not enough to make it a routine problem. Matt’s Exodus Fleet in Becky Chambers’ Record of a Spaceborn Few is a desperate attempt to find a new home; centuries later, with considerable cultural differences, re-contact with Earth. Likewise, Fred Pohl and Cyril Cohen’s “Searching the Sky” generation ships that colonized the closer stars were more than adequate for transporting small groups and the occasional trade cargo. The founder effect and resulting inbreeding drive the plot forward.

Routine contacts can be disrupted by economic, political, or military events. The same Busad ramjet that transported the Quakers to Tau Cetus in Joan Slonczewski’s stationary form at Foxfield may have facilitated the subsequent mission from Earth. Nuclear war prevented interstellar travel, and it wasn’t until enough time passed that Earth’s civilization resumed along a very different route than the Foxfield community. Brian M. Stableford uses this metaphor in his Daedalus series. Dozens of understudied alien worlds have been settled with insufficient technology. Crisis on Earth has forced a long-term hiatus in interstellar travel. A hundred years later, the starship Daedalus sets off to determine whether any of Earth’s children have survived, and if so, how their alien world has reshaped them.

The author cannot overestimate the utility of inconvenient natural events in this matter. Grenchstom’s planet, the setting for Nicola Griffith’s Ammonite, is free to spend a few days independent of galactic culture due to a disease that makes the world a death trap for most visitors. In Michael McCollum’s Antares Dawn, larger events isolate Alta; the supernova reshuffles the folding points upon which interstellar travel depends. Unable to reach other systems, Alta was forced to develop along independent lines. Fortunately for the colonists, their infrastructure was up to the challenge.

In the end, there is nothing more isolating than mutual loathing. Lois McMaster Bujold’s planet Athos is settled by religious extremists determined to avoid the corrupting influence of mainstream civilization. As a result, very few galactics visit Athos, and only an extreme crisis can convince the people of Athos to visit other worlds in the galaxy. The colony set in David Drake’s Hammer’s Slammers is dedicated to displaying nationalist pride – no Johnny Foreigner wants here! – rather than taking financially prudent risks. The result is a large number of communities on the brink of bankruptcy forced to engage by economic realities but lacking the diplomatic skills necessary to avoid violent disputes. This is almost a tailor-made setting for mercenaries to provide regular employment!

No doubt I’ve omitted many options above because I didn’t think of them, or because they were the sixth or greater example of five examples that were decidedly incomplete. No doubt some of you will be kind enough to mention the overlooked options in the comments, which, as always, are below.