OK. So, now we've got working population distribution when we know what the polity looks like from the big picture.
Now, we get to figure out the math, when we don't know any of that, which is the entire goal of this whole system I'm developing.
The players come into a new star system.
We roll the system and it's worlds. We check for native life, and don't find any.
Now, we have to check for life of another E.T., without knowing what the next system past this one looks.
Broadly, there are a few contributing factors:
Have we already met another E.T.? Do we know their core areas, and could this system be part of it? If not, could this system be in their explored zone?
If any of that is yes, then we just follow the rules for that E.T.
If there could be multiple E.T., the one (if any) in the core area gets first crack at all the planets. Then all other E.T. take turns rolling the remaining planets. (Cultures allowing)
If it's in the core zone of multiple E.T., hopefully we already determined that their relationship is like, and follow that.
What if we can't easily tell if the system is in the core zone or explored zone of a given E.T.?
If it looks like it's probably in core or explored zone of a given known E.T. we can do a simple probability based on the TL of the E.T. and the distance to the known core of that E.T. and the distance to the known 'not core or explored zone' of that E.T. I'll write up a chart, core vs explored vs neither. Then we can roll for that E.T as already determined.
But that's all the easy part.
What if we haven't met any other E.T. yet, or the ones we have met are far enough away, we know this can't be in their core or explored zone? What about finding the explored zone of a new E.T even though we're in the core or explored zone of a known E.T.?
If it's within 35 parsecs (roughly one sector) of the homeworld of any known E.T., including the players homeworld, do not roll for new E.T. life. (While this isn't completely accurate, this should make things more playable, and by rolling for native life above you can still meet aliens including E.T. by finding their home system.)
Beyond that, a given system (hex) could be the meeting point of up to 6 E.T. polities. You'll probably have explored at least 3 potential directions already though, so we'll say on average 3 potential E.T. polities (should this be 2? Hmm. No, for the following) but if we're in the explored or core zone of known E.T. then we drop that potential by one for each known E.T that already covers this system.
So, for those 3 potential polities (-1 per known E.T. polity already present) we know the following. And in order to see if there are multiple such polities, if we succeed on any of hte following rolls, then we can roll again for a second polity (if permitted) and if that succeeds, we can roll again for a 3rd polity (if permitted).
The majority (3/4) of E.T polities will be TL11 (core of 3 sectors, explored of 16)
The next most common (5/36) are TL12 (core of 8, explored of 36). And 1/36 will be larger.
Then (1/18) TL10 (core of 1, explored of 4). And 1/36 will be smaller.
E.T. also generate about 1 in 15 sectors. (So I'm defining these 15 sectors as their 'own' sectors.)
So in theory, 3/4 of the time, those ET will explore their own sectors.
1/12, they will not have explored their own sectors.
1/6 will explore their own sectors, and some of their neighbors sectors.
Therefore, if its within 70 parsecs of an E.T. homeworld (roughly 2 sectors), then an unknown polity will have explored that system on a 12 (and therefore, have a chance of having planets, as per it being part of explored space for that E.T.)
No, this doesn't work. This rolls the 1/36 chance every system, but it needs to be a 1/36 overall. 1/36 per system will practically guarantee that there is a TL13+ E.T. nearby. so.. 60*16*2 = 1920 means.. 1/36*1/36*1/36*1/2
So.. per system, we'd have to roll 2d6 and if we get a 12, then roll 2d6, and if we get a 12, then roll 2d6, and if we get a 12, then roll 1d6, and if we get a 4+, then a TL13 E.T. has explored the system and therefore may have a presence as above (11+ on 2d6).
That seems.. completely absurd. What's a better way than rolling 7 dice??