Archive through March 16, 2004

Star Fleet Universe Discussion Board: Prime Directive RPG: NEW KINDS OF RPG PRODUCTS: GURPS Prime Civilians: Archive through March 16, 2004
By Gary Plana (Garyplana) on Tuesday, March 02, 2004 - 06:08 pm: Edit

Garth, re your above: that patrol zone seems awfully big for one ship to cover. Plus it is just a POL, not a CA. I don't know that I would have one ship covering more than five or six hexes.

What ship covers the border and Neutral Zone when the POL is back at 3212? Someone has to do the custom inspections, etc.

By Robert Herneson (Rherneson) on Tuesday, March 02, 2004 - 07:33 pm: Edit

Gary, is there any other source that could be used?
First, TNG and beyond (especially) are very bad at just using things that sound good in the script. Second, those numbers would be from Y225+.
If it can't be found on screen, I'd be more comfortable with novelizations, then broad based fandom material, then lastly TNG for data before anything that came after.

RH

By Jonathan Lang (Dataweaver) on Tuesday, March 02, 2004 - 07:57 pm: Edit

OK: So we've got major and minor worlds which are several hexes apart (From what I see on the map in GPD, it appears that there's typically one major or minor planet within two or three hexes of a given planet), meaning that the "speed of trade" between major industrial worlds tends to be on the order of 500 days, or 42 months. Also according to the map in GPD, there are a thousand stars per hex, averaging one star per 150,000 cubic parsecs, for an average seperation of approximately 30 parsecs, or five days' travel at the speed of trade. About a tenth of those have "planets" (which I'll interpret as "potentially interesting planets"), effectively doubling the travel time between planets, and the impression that I got from GPD is that only about a tenth or so of those are inhabited (somewhere around ten per hex) - that puts the speed of trade between inhabited incidental worlds on the order of three weeks to your nearest neighbor. If something closer to half of them are inhabited (50 per hex), figure on commercial trip lengths of around two weeks or so between nearest neighbors. At the speed of Star Fleet, this would drop to about a week.

For a starship-based civilian campaign, then, we can assume that the crew is going to spend long stretches of time (significant fractions of a year) in transit, as dash speed is rarely affordable. The "90% boredom; 10% stark, raving terror" rule seems quite appropriate here if you interpret "stark, raving terror" as "adventure".

Furthermore, a civilians campaign generally cannot afford to ignore the incidental worlds; you find yourself with travel times in excess of years if you restrict yourself to minor or major worlds - unless you stick to capital sectors.

Comparing this to Traveller: even though ships are much faster in the SFU, trade is going to take longer, with trips between neighboring colonies generally taking about twice as long.

---

How would you map the SFU concepts of "major" and "minor" worlds to rules compatable with GURPS Space' worlds and civilizations chapters? GT: Far Trader gives every world a "trade number" which could be thought of as an order-of-magnitude measure of the strength of a world's economy. The factors used to compute the trade number are, essentially, the world's population rating and a "standard of living" factor. I suspect that this "trade number" would be a viable meter for a planet's "majority" status - say, a trade number of 6 or higher is a Major World; 5 or 5.5 is a Minor World; and anything less than that is Incidental. Thoughts?

By Garth L. Getgen (Sgt_G) on Tuesday, March 02, 2004 - 09:19 pm: Edit

Gary, I editied out some of the dialog from the story ... it's not the only POL covering that sector. There's at least four others with overlapping patrol zones.

The point I was making it just how full space really can be, even with a very loose density of one stellar system per 20 parsecs cubed (7,500 cubic parsec). Now that I relook at those numbers, I'm thinking 200,000 is far too low of an estimate ... it should probaly be an order of magnitude or two higher. I think I divided parsecs by 3.3 to get lightyears, instead of multipled.

~~~~~~~~~~~

Jonathan, where in GPD did you get those numbers of "averaging one star per 150,000 cubic parsecs, for an average seperation of approximately 30 parsecs"?? Is that a direct quote from the book?? If so, what page, please?? I'm looking for it and don't see it.


Garth L. Getgen

By David Lang (Dlang) on Wednesday, March 03, 2004 - 03:26 am: Edit

re: patrol areas

remember that it takes one ship per province (~5-6 hexes) to affect it's status (captured, disputed, etc) so I think a 5 hex patrol area is about right

as for the sizes of the major vs minor planets

the only real info we have is their military budgets, 5EP/turn for a major planet, 3 EP/turn for a minor planet

to put this into perspective
a cruiser costs ~8 EP to build
a frigate cost ~3 EP to build
a Planetary Defense Unit costs 6-7 EP to build (except at the shipyard) plus fighters that cost another 3 EP to build (a minor planet has 2 PDU's deployed, a major planet has 4)

decide what percentage of the planatary budget is going to the military and you can make a guess as to the total cash available (currently the US spends ~3.4% of the GNP on the military)

By Richard Wells (Rwwells) on Wednesday, March 03, 2004 - 04:11 am: Edit

A simple benchmark might be to equate each EP with one billion technological workers (plus appropiate support resources). Home systems have sizable populations but many thousands of small colonies suitable for adventures can be added before they aggregate into a single EP change for F&E. Modify the population equalivence based on underlying technological base and ability to absorb larger military spending.

By Jonathan Lang (Dataweaver) on Thursday, March 04, 2004 - 03:12 pm: Edit

Sorry for the delayed response; computer problems.

GPD states that each hex has a thousand stars and a hundred planets. Each hex is 500 pc across. From that, figures can be derived:

A hex has an area of 216,500 pc^2. I goofed initially and assumed a thickness of 500 pc, for a volume of 108,000,000 pc^3; upon further review, i think that the thickness is closer to 100 pc for a volume of 21,650,000 pc^3. Divide by 1000 stars, and you have either 108,000 or 21,650 pc^3 per star. Taking the diameter of a sphere with that volume as a fair estimate of the average seperation of stars, we get distances of 59 pc or 35 pc - again, I goofed initially and used the radius rather than the diameter as the yardstick.

The spacing of the stars in the real universe in Sol's neighborhood is approximately 20 pc^3 per star; a hex with that density of stars would have 1 to 5 million stars, not 1000. Even allowing for a lower density between galactic arms, I don't think that the average density of stars would be even one order of magnitude below this - that is, a hundred thousand stars is an unreasonably low estimate for the number of stars per hex. If we modify "stars" to mean "stars that could have habitable planets", we _might_ be able to justify an order of magnitude lower; but we're still too low by over an order of magnitude.

Richard: 1 billion technological workers would correspond to the bottom end end of a Population Rating (PR) of 9 in GURPS Space. We would effectively be saying that no single system can have more than 5 billion or so inhabitants, given that no Major World produces more than 5 EPs. Furthermore, even a Minor World would need a PR of 9. Such is the problem of mapping a linear scale to an order-of-magnitude scale.

By Douglas E. Lampert (Dlampert) on Thursday, March 04, 2004 - 03:26 pm: Edit

Richard did specify one billion technological workers (plus appropiate support resources), this will be less than total population by at least a factor of two.

By Richard Wells (Rwwells) on Thursday, March 04, 2004 - 05:51 pm: Edit

Jonathan: Unless F&E changed a lot since the last time I looked at it, several systems have multiple minor and major planets. The solar system produces 16 EP amongst the 4 planets listed in F&E. So depending on one wants to calculate the issue, that might give a system wide population around 20-40 billion depending on how many people are actually employed in significant industrial occupations plus the various other residents.

Still a suggestion for a quickie benchmark, not a comphrensive census. Certainly plenty of slack to increase populations to meet requirements of campaigns.

By Mark Norman (Mnorman) on Thursday, March 04, 2004 - 05:52 pm: Edit

And that factor would probably increase exponentially above a certain size (services for the service workers)

By Douglas E. Lampert (Dlampert) on Thursday, March 04, 2004 - 06:07 pm: Edit

Three words: Children, Retires, Housewives.

Support workers typically outnumber tech workers in any given urban area, but the nonworkers are comparable in numbers to ALL of the workers combined.

The estimate of 20-40 billion total people for 16 billion tech workers is off by roughly a factor of two due to the nonworking groups.

By Randy Buttram (Peregrine) on Thursday, March 04, 2004 - 06:19 pm: Edit

And don't forget the enlightened societies' 'leisure underclass', aka the welfare rolls.

By Jonathan Lang (Dataweaver) on Thursday, March 04, 2004 - 06:30 pm: Edit

OK; 1 billion people = 1 EP/turn (modified for technology base) seems reasonable. Note, BTW, that those who aren't in the workforce are unlikely to outnumber those in the workforce by a significant margin - if they do, more and more of the production of the workforce is going to be 'wasted' supporting the non-workforce.

By Douglas E. Lampert (Dlampert) on Thursday, March 04, 2004 - 06:33 pm: Edit

Randy, in all out war, the welfare rolls/unemployed may be low in numbers.

But you NEED teachers, movers, builders, farmers, nurses, secretaries, HR departments, ..., and you WILL have children, old people, and full time caretakers.

These sorts can easily make up 90% of your total population even in areas where tech work is the main thing. (My area is basically 'single industry, defense and NASA tech', as best I can tell about 10% of the populace is actually employed in that industry or in direct support.)

Now, I tend to assume that F&E planets are mostly significant as 'hubs'. Loss of NYC would cost the US heavily, so if I was making a stratigic game about the USA I might give NYC a very large economic value, but in fact not much is actually produced there. Thus I do not worry much about the massive % of F&E income that comes from a fraction of planets. Those are the 'hub' planets where assembly work is done, records are kept, and corporate home offices live.

By Garth L. Getgen (Sgt_G) on Thursday, March 04, 2004 - 10:56 pm: Edit

Jonathan Lang (Dataweaver): "I goofed initially and assumed a thickness of 500 pc"

That wasn't a goof ... that is the correct value, both per what SVC said and also what my independant research found on the web for the thickness of the Milky Way.

I see you worked out the math for the area of a hex ... I didn't bother when figureing it out for my story. I just used 500^3 per hex, times 12 hexes, to get the 1.5 billion for the patrol area.

On the other hand, I did screw up in figuring spacing between stars ... I must have multiplied lightyears by 3.3, instead of dividing, to get parsecs. Working my math backwards, I'm getting a stellar dencity of one star per 7,500 PC^3, or just shy of 20 parces cubed. That's 66 LY between stars; when real astronomy suggests it'd be closer to 5-10 LY (about 2-3 parsecs)between stars.


Garth L. Getgen

By Loren Knight (Loren) on Friday, March 05, 2004 - 12:59 am: Edit

So, on average, how many stars in a hex?

By Richard Wells (Rwwells) on Friday, March 05, 2004 - 01:19 am: Edit

The number of stars in an F&E hex is probably unimportant; the number of systems with anything of value is more significant. Very marginal systems will probably be ignored after the initial sublight explotaration when just getting to a system is challenge enough. A thousand systems worthy of notice is about all the GM can readily handle.

The SFU is far sparser than our reality where one would expect millions to possibly billions of stars per F&E hex. That would certainly make an atlas of the Federation unwieldly.

By F. Douglas Wall (Knarf) on Friday, March 05, 2004 - 01:46 am: Edit

Star atlases as they currently exist are rather unwieldy. Now consider the number of stars added during the exploration of Federation territory, plus the wealth of additional data that a closeup study of a star and it's planets can produce. An SFU star atlas would probably have to be computerized. It would probably take a whole planet of trees to produce one in book form.

By Loren Knight (Loren) on Friday, March 05, 2004 - 11:00 am: Edit

I just meant from the math given above. I agree it's not real important. I was mostly just curious and though someone would whip out the math and answer real quick. I can figure it out myself.

By Gary Plana (Garyplana) on Friday, March 05, 2004 - 11:58 am: Edit

I also suspect the number of stars per hex is unimportant, but with reason. Worlds important to the SFU have always been placed by hand, ie SVC or SPP, and I do not think that policy is likely to change after 25+ years.

Oh, and don't forget the various arms of the galaxy -- it has been mentioned before so needs to be kept in mind. Stellar density will vary from hex to hex.

If you really need data regarding what's in a hex, then I highly suggest GSSC. This is a computer program SJ Games did (or someone did for them) as a play-aid. You tell it how large a region to map, the base TL in your campaign, etc, and it will generate star systems per the SPACE3 rules.

Complete data. Star color, number of worlds and moons, environmental data, whether they are inhabited and by what, resources, etc.

By Dale Lloyd Fields (Dylkha) on Friday, March 05, 2004 - 12:18 pm: Edit

If anyone is interested...

Local mass density is 0.03 solar masses per pc^3.

Average stellar mass in the solar neighborhood is 0.3 solar masses.

Scale length of the disk R_0 is 3.5 kpc. (kiloparsec)

Scale height of the disk h_z is 0.325 kpc for the thin disk (younger, more metal rich stars aged between 0-10 billion years old) and 1.4 kpc for the thick disk (older, more metal poor stars around 8-12 billion years old).

The disk is exponential in both the radial and vertical directions. You can calculate the local stellar density at any location through the equation:

density = N_0 * exp(-R/R_0) * (exp(-z/h_thin) + 0.02 * exp(-z/h_thick))

where R_O is the scale length of the disk, h_thin (h_thick)is the scale height of the thin (thick) disk, R is the distance from the center of the galaxy and z is the distance off of the central plane of the disk. The sun is 8.0 kpc from the galactic center and about 50 pc (0.05 kpc) from the midplane. N_0 is around 0.02 stars per pc^3 (for stars in the absolute magnitude range 4.5 to 9.5 if one cares).

Integrate to your heart's content. Info is from Carroll & Ostlie's 1996 book, so it may be slightly dated (but not significantly).

By Garth L. Getgen (Sgt_G) on Friday, March 05, 2004 - 06:54 pm: Edit

Dale ... am I to understand that you are making the disk thinner as it gets closer to the edge??? Perhaps I'm wrong, but I thought the galatic disk is fairly uniform in thickness all the way across, save for the Shapely Center of course.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Since I haven't done math lke that since high school, 25 years ago, and we really don't need an exact count for our purposes here, I like calculate it the easy way.

If you use an average of 5 parsecs between stars (and that's on the long end of the scale ... it should be half that!!), and simplfy the hex into a 500x500x500 cube, then there's roughly one million (100^3) stellar objects per hex. At 2.5 parces between stars, it's eight million (200^3) per hex.

Perhaps my story is set in a region between arms of the Milky Way, thus the much lower stellar density. :)


Garth L. Getgen

By Dale Lloyd Fields (Dylkha) on Saturday, March 06, 2004 - 02:18 pm: Edit

Yeah, the Milky War obeys an exponential profile pretty well over most of its extent (generically all spiral galaxies do as well). Spiral arms are star-poor in comparison to the spiral arms, but only have densities (at most) a factor of a few down. Also, when getting large numbers of stars keep in mind that the Milky War is thought to have some 400 billion of them. But...many of them are metal poor and the current research shows the likelyhood of a star having a planet scales with the mean metallicity of the star. Even still, that probably means some billions of stars with planets. We do live in a pretty big galaxy. Hmm, as the more metal rich stars are more likely to have planets, planets are much more likely to be found near the midplane...

That said, please note that these numbers are "real" and thus do not necessarily have to apply to the SFU. SVC has stated that modern astronomers got the Sun-Galactic Center distance wrong and it is really 20 kpc (rather than 8.0+-0.5) so that there will be room for other empires and such in the other parts of the galaxy. If you get semi-reasonable numbers, people like me are not going to complain (well, too much). The Hydrans are a good example.

[Edit: While rereading my first post I realized the comment "Integrate to your heart's conent" would reasonably be taken negatively. My apologies.]

By Dale Lloyd Fields (Dylkha) on Tuesday, March 16, 2004 - 03:31 pm: Edit

[Cranes his head around and sees no one]

Ah, as the last person to post in what used to be a pretty active thread, I hope I haven't caused people to flee in terror. My apologies if so. I promise to be good. Shane! Come back!

By Gary Plana (Garyplana) on Tuesday, March 16, 2004 - 09:25 pm: Edit

So you admit it's all your fault? :)

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