From: james vassilakos Subject: sf-rpg: planet generation To: rhiemeir@ibr.cs.tu-bs.de (joerg rhiemeier), nv91-asa@nada.kth.se (anders sandberg), tlh@epsilon.com (tony hayes), larrys@zk3.dec.com (larry smith) Date: Fri, 1 Sep 1995 19:33:35 -0700 (PDT) Okay, here's what I've got so far... Shares of Likelihood by Orbital Zone Contact Inner Biozone Outer Solar Companion - - - - Gas Giant - 1 2 3 Magma Ball 3 3 - - Primordial - 3 2 - Asteroid - 2 2 2 Planetoid - 2 2 2 Vacuum Ball - 2 2 2 Snow Ball - - 1 3 Ice Planet - - 1 3 Shallow World - 2 2 2 Barren World - - 2 2 Marginal World - - 2 - Garden World - - 2 - Desert World - - 2 - Water World - - 2 - Belch Ball - 2 2 2 Greenhouse - 3 2 1 Exotic - - 2 - Liquid World - - 2 1 Special - - - - Total Shares/Zone 3 20 32 23 Zones: Inner, Biozone, and Outer orbital zones are pretty self- explanitory. The contact zone is that which actually makes contact with the stellar material but is still outside the vaporization radius (this zone can only occur in red giants and some orange supergiants). Factors of Planet Type: So far, according to this system, the only influencing factor of what sort of planet you end up with in a given orbit is the planet's orbital zone. Granted, O, B, and A stars aren't supposed to produce planets due to their ridiculous level of luminosity (and as corroborated by their high angular momentum), however, we only have a few type A stars in the near- star data we're working with, and I think they are all of the smallest type, so I may overlook this consideration. Explanation of Shares: Under this system, the program will first determine the orbital zone of the world it is generating, then it will go to the chart above, map out a probability spectrum, roll the dice, and see which world type gets chosen. So for an outer zone orbit, there is only a 3/23 chance of a gas giant being chosen (this may seem low to you, I dunno). What I need from you: I only assigned 0s, 1s, 2s, and 3s to the chart above, indicating how likely I thought each world type was to occur in each orbital zone. What I need from you are suggestions toward modifying that chart. Other numbers may be used. There is also the latest version of the planetary classification system to consider (presented below). I'm not looking for the absolute in technical sophistication, obviously. Just something easy to work with and somewhat plausible given what little we know about what's out there. Solar Companion: Not technically a world but not the main star or even a part of the close-binary pair. Gas Giant: Fairly obvious. Great for wilderness refueling if you use hydrogen to get around. Magma Ball: Ouch, this place is hot. This planet is either very close to the primary or is on its way to becoming a primordial world. It is possible that such a world is tidally locked to its sun. Then, one half would be a sea of lava, and the other half would be frozen. Primordial: A very young world. Atmosphere poisonous (usually reducing, being composed primally of nitrogen and carbon dioxide with variable amounts of water vapor, ammonia, methane, carbon monoxide and hydrogen sulfide). Geologically instable. Lots of volcanos and magma seas. Asteroid: A large chuck of rock which is part of an asteroid belt. Planetoid: A large chuck of rock which isn't part of an asteroid belt. Not necessarily round. Could be a captured planet. Vacuum Ball: Like the moon, essentially. Lots of rock. No atmosphere. Too big to be called a planetoid. Snow Ball: Like a planetoid, but composed primarily of ice. Usually found only beyond the star's biozone. Ice Planet: May have a breathable atmosphere so long as there is the ecosystem to support it. More likely a dead planet without a breathable atmosphere. Shallow World: Has some atmosphere, but it's not something you'd want in your lungs even assuming there was enough of it to breathe, which there isn't. This place will require gobs of terraforming if you really want to live here, and it probably won't be worth the effort when you're done. Mars might be an example. Barren World: Generally a non-breathable atmosphere, but there will probably be water tied up as ice crystals in the soil. Oxygen will probably reside in oxidizing compounds such as ferric oxide or in various nitrates. World may be volcanically active. Probably on its way to becoming a shallow world. No life beyond bacteria. Marginal World: Complex lifeforms either never evolved on this planet or went extinct sometime within the past couple million years. Perhaps the sun flared and knocked out the entire ecosystem, or maybe a slew of meteors struck, churning up enough dust that the sun was blotted out for several decades. Irregardless, this world is ripe for colonization. Some terraforming will be required, however, if the world is to remain habitable over the long term. Mars might have been a good example eons ago. Garden World: Earth is a prime example. Not only can you breath the atmosphere without mechanical aid, but life, either native or transplanted, thrives in abundance. Desert World: This world isn't entirely desert, but the hydrographic percentage is relatively low. Most likely, the atmosphere is somewhat thin, and the change in temperature from day to night is fairly extreme. Assuming an ecosystem is present, however, the atmosphere is probably breathable. Water World: Over 90% covered by water and ice. Probably a breathable atmosphere. Possibly a teaming native ecosystem which got evolutionarily stuck due to the total lack of any freestanding continents. Belch Ball: Lifeless terrestrial planet with a poisonous, toxic, or possibly even borderline-corrosive atmosphere. Greenhouse: A world gone to hell because of too much greenhouse gases (ala Venus). Exotic World: This planet has life, but not as we know it. The atmosphere is poisonous to humans and may even contain lethal micro-organisms. The temperature, however, is probably moderate enough that an individual can walk around unscathed by the environment so long as he has a self- contained oxygen supply. Many alien homeworlds will be exotics. Liquid World: Surface predominantly covered by ammonia or liquid methane. In the former case, the world may contain a teaming alien ecosystem. In the latter, alien life is less likely. Of course, other (non-water) liquids are also possible. Special: This world cannot be placed in any of the previously defined categories. It may be an artificial planet or perhaps a fluke of nature. GM's discretion advised. From: james vassilakos Subject: sf-rpg: more planet generation To: rhiemeir@ibr.cs.tu-bs.de (joerg rhiemeier), nv91-asa@nada.kth.se (anders sandberg), tlh@epsilon.com (tony hayes), larrys@zk3.dec.com (larry smith) Date: Sat, 2 Sep 1995 15:58:33 -0700 (PDT) I've been fooling around a little with the probability data given in GURPS:Space. Here's a summary of the chances of various stars having worlds (the estimates are a bit high since I didn't take empty orbits into consideration and interpreted the "+2" rule on the margin of p99 to refer to the total roll, rather than per die). Let me know if you think these total figures are screwy or not. I may use this data as a basis for the program I'm working on depending on the responses I get from you folks. OIa: Planets not possible OIb: Planets not possible OV: Planets not possible BIa: Planets not possible BIb: Planets not possible solo binary BII: 0.5% / 0.0% chance of 4 to 19 planets BIII: 0.5% / 0.0% chance of 4 to 19 planets BIV: 0.5% / 0.0% chance of 4 to 19 planets BV: 1.9% / 0.0% chance of 3 to 18 planets AIa: 0.5% / 0.0% chance of 6 to 21 planets AIb: 0.5% / 0.0% chance of 5 to 20 planets AII: 0.5% / 0.0% chance of 5 to 20 planets AIII: 0.5% / 0.0% chance of 4 to 19 planets AIV: 1.9% / 0.0% chance of 3 to 18 planets AV: 4.6% / 0.5% chance of 2 to 17 planets FIa: 1.9% / 0.0% chance of 6 to 21 planets FIb: 1.9% / 0.0% chance of 5 to 20 planets FII: 1.9% / 0.0% chance of 4 to 19 planets FIII: 1.9% / 0.0% chance of 3 to 18 planets FIV: 9.3% / 1.9% chance of 3 to 18 planets FV: 83.8% / 62.5% chance of 2 to 17 planets GIa: 9.3% / 1.9% chance of 6 to 21 planets GIb: 9.3% / 1.9% chance of 5 to 20 planets GII: 9.3% / 1.9% chance of 4 to 19 planets GIII: 9.3% / 1.9% chance of 3 to 18 planets GIV: 16.2% / 4.6% chance of 2 to 17 planets GV: 98.1% / 90.7% chance of 1 to 16 planets GVI: 98.1% / 90.7% chance of 3 to 13 planets KIa: 50.0% / 25.9% chance of 5 to 20 planets KIb: 98.1% / 90.7% chance of 5 to 20 planets KII: 98.1% / 90.7% chance of 4 to 19 planets KIII: 98.1% / 90.7% chance of 3 to 18 planets KIV: 98.1% / 90.7% chance of 2 to 17 planets KV: 98.1% / 90.7% chance of 1 to 16 planets KVI: 98.1% / 90.7% chance of 3 to 13 planets MIa: 98.1% / 90.7% chance of 3 to 18 planets MIb: 98.1% / 90.7% chance of 3 to 18 planets MII: 98.1% / 90.7% chance of 3 to 18 planets MIII: 98.1% / 90.7% chance of 3 to 18 planets MV: 98.1% / 90.7% chance of 1 to 16 planets MVI: 98.1% / 90.7% chance of 4 to 14 planets