Re: [Space] How habitable is my universe?
 

I have a PHP script to generate systems as per GURPS Space, with a very few minor tweaks (Agemegos' revised tidal formulae and aging the system in 0.1Gy blocks to track changes over stellar evolutionary timescales). I use the chart in G:S to generate stellar types instead of real-universe data. Also, I use all the rules except for brown dwarf and flare star generation.

I've generated a total of 16977 systems this way (I have a perl script that creates whole thousand-system sectors at once). The habitability breakdown is as follows:
(Without diving into the tables right now, I suspect that the NULL values are from systems with nothing but gas giants and belts.)

I'm at work and without my books, but I was under the impression that you didn't even generate carrying capacity for Hab 0 planets -- the assumption was that Hab 0 systems would only ever have outpost-type residents (miners, military, etc.).

Re: [Space] How habitable is my universe?
 

I am perhaps confusing the population rules in Space with those in GT: Interstellar Wars.

Re: [Space] How habitable is my universe?
 

Which is why I haven't done it, either.

Yes and no. The range for each variable is already constrained because we're necessarily talking about habitable worlds. As long as the bins are wide enough, the combinations will still result in a jackpot fairly frequently.

I don't think so, unless I missed something important.

What we have is two categories -- hostile (habitability 0) and habitable (habitability >0) -- with a probability function to choose between them, e.g. f(0) = 0.9. Within the habitable category, there is a roughly bell-shaped distribution of habitability with a central peak defined by how wide are the bins (i.e., how likely are the optimum results) in each variable.

Re: [Space] How habitable is my universe?
 

Hmmm. On review, you're right. This is a significant departure from earlier uses of "habitability," and a flaw in the system in my opinion. I don't see the point of discussing or measuring the "habitability" of any world which cannot support human life in the open somewhere on its surface. Sealed habitats and life support are pretty much the same, no matter where one goes, and it's pointless to assign them a "natural" carrying capacity.

As for worlds with Toxic or Corrosive atmospheres, the answer is that one would not "colonize" them at all, when it would be simpler and safer to construct an orbital habitat or one on a nearby asteroid or moon. If there were valuable resources to exploit or interesting aliens to contact, one would build an outpost instead, which does not depend on carrying capacity (p. 93), and support it from a colony somewhere more convenient.

Re: [Space] How habitable is my universe?
 

Ah, of course, you're right. I'm just the kind of guy that likes to know that kind of stuff, I suppose for "error checking" purposes or what have you, but it shouldn't be in the final output. My bad.

When it all comes down to it, information about the star system is mostly irrelevant anyway; that's pretty much why most Traveller maps show only the main world's name, whether it's high pop, and the fueling, repairing, and trading possibilities. If you're looking to map out an unexplored section of space, you want to know spectral type to help narrow down where good worlds are more likely to be (and how far from the sun to look for them), and if you're in charge of sending out colony ships and have to make a report to the Emperor, you're not going to show him tons of details, you're going to show him a few pieces of information and ask him to point to the ones he wants colonized.

Or something like that.

Re: [Space] How habitable is my universe?
 

Why is that so bad ? Such a world would have a breathable atmosphere and temperate climate. The water may be frozen, but you only have to get ice to warmer areas to have sunshine melt it. That´s a lot better than what we have on mars for example.

Re: [Space] How habitable is my universe?
 

It's not totally pointless; which resources and hazards are present in the environment makes a big deal on how challenging life support is.

Re: [Space] How habitable is my universe?
 

Is Habitability calculated before or after length of day?

Re: [Space] How habitable is my universe?
 

Is raw vacuum in orbit "habitable"? If not, then assigning a "habitability" rating to worse conditions is pointless.

My objection is that GURPS Space 4/e altered the commonly accepted definition of "habitable," one that has been used consistently in previous SJ Games products. "[A] summary of all the factors that make a world pleasant to live on," should, in fact, imply that it is even possible for humans to live on the world, as opposed to in artificial habitats that happen to be located there.

The proper place to include the relative difficulty of living on uninhabitable worlds is in the calculation of affinity. GURPS Space 4/e unnecessarily confuses the two.

Re: [Space] How habitable is my universe?
 

Dumb question time:

Could the Hab rating be the best you can make it with the aid of some terraforming, rather than the way you found it? I mean, it seems to me that the Hab4 ball just described could have an atmosphere built and regenerated, and the humans inhabit it on the twilight edges. Sure, the atmosphere escapes over time, but that's not a problem for anyone currently alive.

With the twilight band having a tolerable level of atmosphere and heat, maybe in a few hundred years some of the day heat will transfer over to the night side and release the water. So long as the atmosphere-making machines are running, it could become a regular, habitable, tide-locked world, up to whatever Hab4 means.

The alternative seems to be then, that there are even fewer habitable worlds.