Build A World! Part One

I want to create a star system and habitable world for a mixed colony. Of course, I start with the big picture…

Star density, from GURPS Space 1st Edition, is 1/36 parsec / 3.26^3 = .0008 stars per lyr^3. Times 100^3 = ~802 stars in one million lyr^3, a cubic light century.

 

A quick and dirty take on the Drake equation- one in seven stars with living worlds, one in seven living worlds with complex ecologies, one in ten have smart critters, one in ten have cities and civilization, one in ten of those have spacefaring natives… 7*7*10*10*10=49,000 star systems

 

7 seven space faring times 49,000 = 343,000 star systems in campaign space, a sphere of 343,000*36*3.26^3 = ~428 million cubic light years, (4.2781E8/pi*.75)^(1/3)*2 = 934.9 light years across.

 

Using GURPS' 30-day rule, the average speed of FTL is ~1.3 lyrs/hr (934.9 lyrs / 30 days = 31.2 lyrs / 24 hrs = 1.3 lyrs/hr).

 

What I would normally do at this point is use a spreadsheet to randomly generate the locations and masses of the spacefaring home-stars and mother-worlds. In this case, a box the diameter of the campaign-space high, wide and deep. Generate 2Xs as many and delete the ones which aren't in the sphere (within radius of the central point closest to the main spacefaring species, which has a one in n-spacefaring species of being human, or maybe the humans aren’t even! 8-), which might leave me with extra, unknown spacefaring, hmm...

box of stars
934.9	ly across
#	X	Y	Z	distance
1	120.9	16.4	-88.7	150.8
2	60.9	-154.5	15.2	166.8
3	-254.5	51.8	-151.1	300.5
4	311.1	32.3	-149.1	346.5
5	49.4	-94.9	348.3	364.4
6	-37.4	-385.2	2.4	387.0
7	233.4	309.6	-147.1	414.7
8	230.3	204.2	295.1	426.4

Another sheet would be a time and distance chart; the closer the spacefaring species, the more they interact and compete. This is a map of enemies and enemies of enemies!

#	1	2.0	3	4	5	6	7	8
1	0.0	208.8	382.2	200.2	456.6	441.2	319.4	441.1
2	208.8	0.0	411.9	352.8	338.6	251.1	521.0	485.5
3	382.2	411.9	0.0	565.9	602.7	511.5	551.8	676.3
4	200.2	352.8	565.9	0.0	576.3	564.5	288.0	483.1
5	456.6	338.6	602.7	576.3	0.0	459.8	665.5	353.6
6	441.2	251.1	511.5	564.5	459.8	0.0	760.5	710.4
7	319.4	521.0	551.8	288.0	665.5	760.5	0.0	454.6
8	441.1	485.5	676.3	483.1	353.6	710.4	454.6	0.0

Spacefaring Species One interacts heavily with 2 and 4; Species 2 interacts heavily with 1 and 6... Assuming One is the first spacefaring species, it has interacted most often with 2 and 3, and 3 is not close to any other species. Four is close to one, closer than 2 is to 1, and probably sees 2 as the enemy of its' enemy. They are more likely to cooperate against 1 and oppose 1; 1 is close to all other spacefaring species and more likely than any other to be in some conflict with all other species. The others are fairly far apart and only 6 and 2, and 7 and 4, are nearly as close to each other as 1 to 2 and 4. Four and 7 might both like the same rare type of world...

Once I have the masses of the stars involved, weighted towards K and G, orange and yellow, I can estimate how many sols worth of light and heat they put out, and the goldilocks zone. The masses of each world, planet or gas-giant moon, are similarly weighted towards one Earth, and hydrographic ratio upwards of .5^.5 = 0.7071 the surface area.

 

In my campaign space, there are 7 spacefaring species, one of which is the big kahuna, 63 more developing civilizations, one of which may very well be humankind, nearly 630 smart critters which might or might not be ignored as animals, seven thousand worlds with complex ecologies and another forty thousand living worlds. There might be millions of terraformable worlds, but my guess is there are too many 'good enough' worlds for that to happen. There will be a few barely-good-enough hard-luck colonies settled for good reason and re-engineered into garden worlds.

 

Oh dear, I haven't even gotten to my campaign world yet...

http://vincesalienzoo.blogspot.com/2015/02/build-world-part-two-oh-dear-i-havent.html