We were recently asked (indirectly) how clusters in Diaspora are connected together. The short answer, promptly given, is that they aren’t. A cluster is a group of some small number of systems linked together by an unknown geometry underlying the universe that perhaps changes slowly and perhaps not. The systems could be any distance apart and the links can be traversed instantaneously with the right technology.

Okay, so because that’s basically a setting axiom, I don’t feel obligated to explain it in terms of setting logic. It’s just true.

So presumably what is interesting to talk about here is why it’s true in terms of game design — why did we make that choice.I can’t speak for all four authors, obviously, but I will anyway. They can chime in in the comments to call me a liar. As always, memory is 5% stored data and 95% local fabrication, so this is my post-invention invention of why we did this.

Constraints are fun and infinity is hard. Having clusters consist of a small number of systems constrains what you can do, and this lets you focus. You will find that because of this each cluster has its own character and therefore tells its own stories. We wanted to encourage you to (and take a deep breath, preparing for heresy) make new characters and clusters often. If your campaign is awesome for six years straight, more power to you, but I personally am a fan of stopping the second it gets dull and starting over. So character generation is fun and cluster generation is designed to give you somewhere new and refreshing to play. My attention span is about four to ten sessions.

This small number of worlds is also small enough to get developed at the table. In one evening you will have characters, a place for them to find adventure, and explicit connections between the characters, their environment, and each other character. You can’t do that with an open map — there must be places that lack detail to some extent because that’s just how infinity works.

If you love your characters but want a novel place to adventure (either to scratch the itch of experiencing new worlds or the itch of exploring the unknown or to support an event in-story) that’s easy enough — the cluster system is also intentionally modular. Make a new cluster. Connect the last system in the old cluster to the first system in the new cluster. Done! So the system is secretly infinite but we don’t start you there because you can’t spend infinite time in the first session. In the programming world this is sometimes called “just in time development” and the principle is simple: don’t build something you don’t need yet, but build an infrastructure that lets you add it fast exactly when you do.

There is another reason to make clusters finite and it’s more related to setting design than story design. Earth is not one of these worlds.

The essential mystery in Diaspora is Earth. Where is it? If this is how faster-than-light travel works, how did we get here from Earth? Why the diaspora? What is happening on Earth now (though as I touched on briefly yesterday, that question might as reasonably be asked with “when” as “where”…) and is it going to happen in this cluster soon? Has it already? Is this even the same universe that contains Earth?

These are questions that I wanted to exist and I certainly did not want to answer (and here’s my canon promise: I will never create a canonical story about Earth — it is certainly and forever yours to deal with or not as you see fit). And so disconnecting the play space from Earth by thousands of years, unknown distance, and an apparently insurmountable technology barrier leaves that mystery intact and its resolution entirely in your hands. And you may find a different answer in each campaign you play, or never find it.

So the closed cluster gives you a small enough playground to invent it in detail in one evening and amusing mysteries of grand scale to play with. It grants comfort to players and wonder to characters. And, with luck, the potential for awe, which is a holy grail for great science-fiction play in my books.

–BMurray