Steve Jackson Games - Site Navigation
Home General Info Follow Us Search Illuminator Store Forums What's New Other Games Ogre GURPS Munchkin Our Games: Home

Go Back   Steve Jackson Games Forums > Roleplaying > GURPS

Reply
 
Thread Tools Display Modes
Old 03-15-2013, 10:15 PM   #131
Agemegos
 
Agemegos's Avatar
 
Join Date: May 2005
Location: Oz
Default Re: [Space] GURPS Handbook of the Planets

Quote:
Originally Posted by Celti View Post
Brett, have you considered a Pyramid article on what you view the Space generation sequence should be?
No, I can't say that I have. Nor am I qualified to write one.

Besides, the existing world-building sequence is 72 pages. You wouldn't get an improved version into an issue of Pyramid even with minimal explanation. And its the explanation that readers would really want. System generation is sufficiently complicated and easily so tedious that actually executing the steps is definitely work for machines.
__________________

Decay is inherent in all composite things.
Nod head. Get treat.
Agemegos is offline   Reply With Quote
Old 03-15-2013, 10:29 PM   #132
Celti
 
Celti's Avatar
 
Join Date: Jun 2007
Location: USA, Arizona, Mesa
Default Re: [Space] GURPS Handbook of the Planets

Quote:
Originally Posted by Brett View Post
No, I can't say that I have. Nor am I qualified to write one.
The discussion in this thread seems to indicate that you're better-qualified than some, but I'll let that rest.

Quote:
Originally Posted by Brett View Post
Besides, the existing world-building sequence is 72 pages.
That, I completely didn't think about. Bit long for Pyramid, yeah. Oh well.
Celti is offline   Reply With Quote
Old 03-15-2013, 10:37 PM   #133
Agemegos
 
Agemegos's Avatar
 
Join Date: May 2005
Location: Oz
Default Re: [Space] GURPS Handbook of the Planets

Quote:
Originally Posted by Celti View Post
The discussion in this thread seems to indicate that you're better-qualified than some, but I'll let that rest.
Well, better-informed, anyway. There are people with no training in the physical sciences or mathematical modelling at all. Quite a lot of them. They are rich in other ways.

SJ Games likes its publications on technical topics to be written by qualified experts, or at least to have qualified experts on the writing team. I may be better informed on planetology than the usual dilettante, but dilettante is all I am. I impress laymen and exasperate experts.
__________________

Decay is inherent in all composite things.
Nod head. Get treat.

Last edited by Agemegos; 03-15-2013 at 10:41 PM.
Agemegos is offline   Reply With Quote
Old 03-16-2013, 12:37 AM   #134
sir_pudding
Wielder of Smart Pants
 
sir_pudding's Avatar
 
Join Date: Aug 2004
Location: Ventura CA
Default Re: [Space] GURPS Handbook of the Planets

Quote:
Originally Posted by Brett View Post
SJ Games likes its publications on technical topics to be written by qualified experts, or at least to have qualified experts on the writing team. I may be better informed on planetology than the usual dilettante, but dilettante is all I am. I impress laymen and exasperate experts.
Dan Howard isn't a professional hopologist. David Pulver isn't an engineer. Jason Levine isn't psionic.
sir_pudding is offline   Reply With Quote
Old 03-16-2013, 02:09 AM   #135
Agemegos
 
Agemegos's Avatar
 
Join Date: May 2005
Location: Oz
Default Re: [Space] GURPS Handbook of the Planets

Quote:
Originally Posted by sir_pudding View Post
Dan Howard isn't a professional hopologist. David Pulver isn't an engineer. Jason Levine isn't psionic.
No? Well, I guess that being a good and reliable writer and easy to work with is an acceptable substitute for formal qualifications. I'm not any of those things, and besides I don't want to design a pencil-and-dice star system generator. For one thing I don't feel sufficiently confident of my own expertise.
__________________

Decay is inherent in all composite things.
Nod head. Get treat.

Last edited by Agemegos; 03-16-2013 at 02:30 AM.
Agemegos is offline   Reply With Quote
Old 03-16-2013, 05:00 AM   #136
Nemoricus
 
Join Date: Mar 2013
Default Re: [Space] GURPS Handbook of the Planets

Quote:
Originally Posted by Whill View Post
A gas giant can only have a moon system that totals no more than .4 Earth masses? If that is in the GURPS Space system, I missed it. Or is that in reality based on current science?

So does this mean I can't have even 1 Earth-massed moon around my gas giant? If these more massive major moons just can't form there, are there any plausible migration/capture scenarios that could account for them being there?
It's a general rule that a gas giant will have a total mass of moons equivalent to about 1/10000 of its own. However, it's not a hard and fast rule, and in our own solar system it varies from about 1/1000 to 1/4000. Since it's possible that this could vary more, I'd say that as long as your gas giant has at least 1000 Earth masses, you could probably have an Earth sized moon without raising too many eyebrows.

Quote:
Originally Posted by Brett View Post
My grasp of physical chemistry is weak, but perhaps it would be possible to use a weighted average of the the specific heats of the chief constituents.
As an approximation, that should be fine.

Quote:
  • I replaced the method for resoving the Ocean/Garden ambiguity, which multiplies the age of the system by the level of visual illumination on the planet, and then compares that to a randomly determined expected time of oxygen catastrophe.
  • I coded a modifier to temperature for worlds with water oceans and active volcanoes or tectonics, to reflect stabilisation of the temperature at about 15 C by the carbonate-silicate cycle.
  • Instead of using Space's "habitability" score I determine factors.
What's the general formula you use for these?

Quote:
Originally Posted by Brett View Post
No? Well, I guess that being a good and reliable writer and easy to work with is an acceptable substitute for formal qualifications. I'm not any of those things, and besides I don't want to design a pencil-and-dice star system generator. For one thing I don't feel sufficiently confident of my own expertise.
No writer is perfect, especially when they first start out. Still, my impression is that you could write a fairly good star system generator and accompanying explanation, based on the posts I've seen from you. And as a star system generator will necessarily include simplifications and approximations for the sake of usability, imperfections in understanding are not a particularly problem. Especially since our understanding of extrasolar planetary systems is quite rudimentary as it is. Verisimilitude is therefore the primary goal.

However, it would be quite a lot of work to design a star system generator, and it serves a very niche market....
Nemoricus is offline   Reply With Quote
Old 03-16-2013, 08:51 AM   #137
Agemegos
 
Agemegos's Avatar
 
Join Date: May 2005
Location: Oz
Default Re: [Space] GURPS Handbook of the Planets

Quote:
Originally Posted by Nemoricus View Post
What's the general formula you use for these?
A series of rudimentary hacks. I'm particularly dissatisfied with me handling or temperature, which would be much better if I modelled meridional transport of heat and then used geometrical expressions for how much of the planet is warmer than 30C or cooler than 0C. They would have given me windiness/storminess too. But I got cold feet about the effects of planet size, atmospheric mass, and rotation.

Quote:
However, it would be quite a lot of work to design a star system generator, and it serves a very niche market....
Indeed. I don't think there is any point in designing and even-more-detailed star system generator than that in GURPS Space 4th ed., which is already much too tedious to use. Computer generators are obviously the way to go.

And as much as I able able and willing to work, I am working on something else. SJ Games doesn't want to publish it (it's on the anti-wish list), and they don't want to work with unreliable writers with obscure and elliptical styles like me. But a new dice-and-pencils star system generator would both be unpublishable and not satisfy my creative urges.

I have lately been driven by the flapping sound and rumbling wheels of a certain chariot to dynamite the logjam of things I ought to be working on. The starsystem generator is one of the casualties. It isn't going to come about, because what I have is good enough for what I have to do.
__________________

Decay is inherent in all composite things.
Nod head. Get treat.
Agemegos is offline   Reply With Quote
Old 03-16-2013, 05:45 PM   #138
Nakawaros
 
Join Date: Feb 2013
Default Re: [Space] GURPS Handbook of the Planets

On a side note, if I'm lucky, I'll have about another... 3 days before I can get a test build up. The orbital mechanics are the problem (placing orbits) but I'm working on a way to do that. I think.
Nakawaros is offline   Reply With Quote
Old 03-17-2013, 10:34 AM   #139
Whill
 
Join Date: Mar 2013
Location: Columbus, Ohio, USA, Earth, Solar System, Milky Way, Whills Universe, Whills Multiverse
Default Re: [Space] GURPS Handbook of the Planets

Quote:
Originally Posted by Nemoricus View Post
Since it's possible that this could vary more, I'd say that as long as your gas giant has at least 1000 Earth masses, you could probably have an Earth sized moon without raising too many eyebrows.
How about 2 or 3 Earth-sized moons? Possibly harsh yet still habitable for hardy species? Pushing it too far?

Quote:
Originally Posted by Nemoricus View Post
It's a general rule that a gas giant will have a total mass of moons equivalent to about 1/10000 of its own. However, it's not a hard and fast rule, and in our own solar system it varies from about 1/1000 to 1/4000.
This strikes me as odd. 1/1000 to 1/4000 > 1/10000. Our system's gas giant moons are the only gas giant moons who existence is even confirmed so far. If our system varies from 1/1000 to 1/4000, what could they possibly be basing that general rule for gas giant moons in the universe at large on anyway?
Whill is offline   Reply With Quote
Old 03-17-2013, 11:52 AM   #140
Nemoricus
 
Join Date: Mar 2013
Default Re: [Space] GURPS Handbook of the Planets

Quote:
Originally Posted by Whill View Post
How about 2 or 3 Earth-sized moons? Possibly harsh yet still habitable for hardy species? Pushing it too far?
You're pushing it, yes. A 4000 Earth mass gas giant could conceivably get away with it, but it's a stretch.

Quote:
This strikes me as odd. 1/1000 to 1/4000 > 1/10000. Our system's gas giant moons are the only gas giant moons who existence is even confirmed so far. If our system varies from 1/1000 to 1/4000, what could they possibly be basing that general rule for gas giant moons in the universe at large on anyway?
I typoed the first one. It should be 1/10000, and it roughly corresponds to Uranus and its moons. Also, according to models people have constructed, 1/10000 should generally hold even for extrasolar gas giants. Have a look at this paper for more information: http://www.nature.com/nature/journal...ture04860.html
Nemoricus is offline   Reply With Quote
Reply

Tags
planets, space, star system generator, system generation, world generation

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Fnords are Off
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 05:17 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.