It's not the size, it's what you do with it that counts.

[gridlore]

Get your minds out the gutter, I'm ranting about Terran Empire again.

In this book, the Empire covers roughly 1/5th of the galaxy. Let us ponder that for a moment. Our galaxy contains roughly 400 billion stars. 20% of that number is 80 billion. 80 billion stars in the empire. Way too fucking big.

Let's look at the local region, out to about 50ly from Earth. According to my sources, that gives us 998 stars, 211 of which are considered to be good candidates for life-bearing systems.

Map of all known stars within 50 light years

A thousand star systems should be plenty big enough for anyone!

Now let's play with some assumptions. Let's say that only 1% of those probably habitable systems has a world that humans can live on without much aid (garden worlds, much like Earth.) Another 5% or so fall into the "close, but no cigar" realm.. one or more factors renders the place less than ideal for humans, but still livable (extremes in temperature, high/low O2 levels, high surface UV exposures, whatever) That gives us 2 twins of Earth, and 11 near-misses. There are you core systems, the ones that will grow quickly and become the population centers.

Not that I'm being extremely conservative with these numbers.

Now, travel times. During the Roman Empire, no place the empire controlled was more than six months away from the capital. Sounds like a good goal. To get out to 50ly from Earth in 6 months will take an engine that moves you (somehow) 100 times faster than light. Call this the average cruising speed of military vessels. So how long to get from Earth to Luyten's Star?

The distance is 12.388ly. Dividing by 100 gives us 0.12388. Multiplying by 365 gives 45.21 days. A month and a half. Good. Starships in this setting are going to be akin to the luxury liners of a bygone age. Of course, the Captain could order full power (130c) and cut nearly two weeks off the journey.

Yes, my game setting is starting to gel nicely...

Comments

[cmdr-zoom.livejournal.com]

I would suggest making one of those 11 near-misses be a world that SHOULD be a garden, except that the local life doesn't play well with Earth life. Not in an insanely-hostile fashion, with toothy acid-blooded things everywhere ... just pointing out that sometimes, a world WITHOUT an existing ecosystem can actually be less hassle.

[isomeme.livejournal.com]

I know it breaks the feel, but I'm all but certain that any starfaring future civilization will regard large planets, even habitable ones, as quaint luxuries, suitable for luxury-goods production and parkland, but no much else. Once you can mine asteroids and comets, and have drives capable of crossing interstellar distances, it's just easier and safer to build habitats than to colonize planets. Habitable planets have inconveniently high gravity and dense atmospheres, making them expensive to ship to or from. And they are prone to annoyances like weather and vulcanism and other unpleasant surprises which the space-borne will not want to deal with.

Actually, this could be a cool way to organize the campaign, and one that would mess with preconceptions -- lovely garden worlds are expendable, but chunks of high-grade chondrite with established mining infrastructure (including a thriving colony) are not.

[10binary-cats.livejournal.com]

or...of your looking for game props try this:

http://www.bathsheba.com/crystal/starmap/

i want one just in case i get really lost. Really really lost.