GURPS Space: I want larger star sizes.

[ericbsmith]

Originally Posted by naloth

You could describe any campaign choice that way.

You could, but do you want campaign choices that are "[MAGIC] because [GM] says so" or do you want campaign choices that make sense with some basis in reality?

Originally Posted by naloth

The fact is there may be motivations for settling in those locations. You listed a nearby resource. It may be a useful way point or military location between a several more appealing locations. It may be something someone very eccentric did just because they could.

If you're talking about a society that can literally build planets and travel across the galaxy there are very few resources that are available at a B-class star that can't be found at an M-class star a few light years away. As I believe I said, there may be outposts, research bases, etc, but you are very very unlikely to find a world that almost certainly had to be manufactured and terraformed around such a star. The resource available there would have to be utterly unique, which also happens to makes it a contrived reason for your story.

[Johnny1A.2]

Originally Posted by dcarson

Reasons why.

Length of wormhole/warp point is proportional to mass of star it is near so large stars give long distance access.

Along with terraforming planets around it they started a stellar lifting program that is still running.

The representatives of Sectors 30, 31, and 32 want funding for terraforming projects in their sectors. They've got good stars, good candidate worlds, and it makes good economic sense, but they don't have the votes unless the representative of Sector 83 votes with them.

What does he want? Well, it so happens that the construction companies in his sector need work, and a good way to get it would be a terraforming project in Sector 83. It also so happens that terraforming projects make good PR at election time. Sector 83's worlds are mostly around B and A stars, but if they want Representative Gorvaksiao's vote...it also turns out that Gorvaksaio happens to know a few juicy things about the Representative for Sector 32 and what she got up with her spouse and that 'escort' on a public junket a few years ago... and of course there's that brother-in-law of the representative of Sector 31 who really, really could use an endorsement in his run for planetary governor...

"We can throw it in with the projects in 30, 31, and 32 in the omnibus."

"The Planning Office says the long term ROI on terraforming planets of A and B stars is something like 30 cents on the dollar!"

"Well, if you don't want my vote for the bill..."

The number of enormous projects that have been built for just that sort of reason would astound the naïve.

[Johnny1A.2]

Originally Posted by ericbsmith

You could, but do you want campaign choices that are "[MAGIC] because [GM] says so" or do you want campaign choices that make sense with some basis in reality?

If you're talking about a society that can literally build planets and travel across the galaxy there are very few resources that are available at a B-class star that can't be found at an M-class star a few light years away. As I believe I said, there may be outposts, research bases, etc, but you are very very unlikely to find a world that almost certainly had to be manufactured and terraformed around such a star. The resource available there would have to be utterly unique, which also happens to makes it a contrived reason for your story.

You're still trying to ascribe decisions to logic and rationality. That's not something you can rely on.

[ericbsmith]

Originally Posted by dcarson

Reasons why.

You're contriving reasons. You can use magic handwavium to contrive any reason your heart desires. That doesn't make the reason any less contrived. Nor does it make the decision to place a habitable planet around a B-Class star any more logical absent your contrived reasons.

So, yes, if you use handwavium to make anything possible. Or you could just as easily use that same handwavium to make it impossible. It's still handwavium.

[Phantasm]

I second the building of antimatter factories in the form of a Dyson sphere around the B- and O-type stars. If you're super-lucky, you may even be able to contain the supernova those stars will probably release, and study the creation of an F- or A-type with planets inside the sphere, not only as long-term antimatter production, albeit at a reduced rate, but long-term research to watch the system form under "controlled" conditions.

You'd need the resources of a few hundred other nearby stars, but for a fifty thousand year old TL12+ galactic-sized nation-state that may be no problem . . . provided you get it past the finance committees.

[AlexanderHowl]

Actually, the amount of material in interstellar space is 10^-16 kg per cubic meter, 1% being dust by mass, meaning that every cubic ly possesses enough mass for over 40 Sol Systems, so a civilization of that level does not need to dismantle star systems, they just need to gather dust.

[Agemegos]

Originally Posted by AlexanderHowl

Actually, the amount of material in interstellar space is 10^-16 kg per cubic meter, 1% being dust by mass, meaning that every cubic ly possesses enough mass for over 40 Sol Systems, so a civilization of that level does not need to dismantle star systems, they just need to gather dust.

"Just".

ten characters

[AlexanderHowl]

If you are building Dyson Spheres around B-type stars, gather interstellar dust is really not that much of a problem. For example, you could use a spacecraft with a magnetic sail with a radius of one light-second to gather the material (it is already a plasma). At 0.01c, it would gather 84,000 metric tons per second (over two trillion metric tons per year).

Of course, you would need a spacecraft large enough to take advantage of that level of harvesting, which would mean that you would need an SM+27 spacecraft. Since a refinery of that size processes 50 billion metric tons per hour, it would be better to have a smaller ship in the hanger with the actual refining equipment (SM+23). With a capacity of 1.5 trillion metric tons (50% fuel tanks), it would take five months to fill the spacecraft. Of course, we are assuming a minimum of some limited form of FTL and reactionless drive, otherwise it just takes too long.

In order to finish the project in ten thousand years, assuming that you use fusion to turn the hydrogen into heavier materials, you would likely need 2×10^30 kg of material. That would require around 70 billion such spacecraft, with a combined mass of 2.1x10^23 metric tons (around 0.01% of Sol). The energy levels required for such an endeavor would be simply incalculable, so there is a question of whether it would be worthwhile, but it would be impressive.

[whswhs]

I really don't think I would try to rationalize having sapient life on planets of huge stars, at least not as a possible result of random dice rolls. The astrophysics just seems to be against it. I might conceivably custom design a specific planet orbiting a specific star, but only if I had a particular narrative in mind.

On the other hand, if I wanted to emulate older science fiction, which tended to have galactic "sectors" or "provinces" based at highly visible stars whose names most readers would know (Aldebaran, Procyon, Sirius, Vega, and so on), I would just assume away the issues with stellar lifespan. I made up custom planetary design rules for "ancient, dying Mars" and similar worlds in GURPS Adaptations; it should be possible to make up comparable rules for giant stars and their planets, reflecting what people in earlier decades thought about astrophysics.

[Rupert]

I would assume that sectors named for such stars are simply so-named because they are the big, bright, obvious star in that sector, so it's named after them. Of course this doesn't fit some of the old stories, which have large stars having correspondingly large solar systems, full of habitable planets (though some such stories also say that these systems are apparently engineered by some mysterious and now vanished civilisation).

One conceit I like for such universes is that massive stars have more FTL links (of whatever sort that universe has) to other stars than less massive ones, so they tend to end up as hubs. Thus even if they have no habitable planets there's a incentive to set up stations and/or terraform any planets that are candidates for such processes.