Are you satisfied with the way systems are generated?

[Ulsyus]

I think so.

Take a look at the table of contents and index:

Okay, there's a fair bit in that. They may be equal but different. Without having it at hand, TWBH had a fair bit of capacity put into social and technological explanations about where the society on a world was at.

Being months away from home still is when I wish they had it up on DriveThru...

 

[Keklas Rekobah]

Okay, so here's a very basic way of replacing the Bode's Law orbit determination with something that more closely resembles a "realistic" method involving orbital harmonics.

The example system shows only the star and planets. Moons, rings, and other objects orbiting the planets were not included for simplicity's sake.

The table translates a 6D (or 6d6) roll into integer ratios of periods between adjacent orbits. These ratios are converted into decimal multipliers for orbital periods and an orbital radius. Assumptions and knows are listed, a procedure is spelled out, and an example system is given.

6D:	Prat:	Pmux:	Rmux:
  6	10:9	 1.111	 1.073
  7	 9:8	 1.125	 1.082
  8	 8:7	 1.143	 1.093
  9	 7:6	 1.167	 1.108
 10	 6:5	 1.200	 1.129
 11	 5:4	 1.250	 1.160
 12	 9:7	 1.286	 1.183
 13	 4:3	 1.333	 1.211
 14	 7:5	 1.400	 1.251
 15	10:7	 1.429	 1.269
 16	 3:2	 1.500	 1.310
 17	 8:5	 1.600	 1.368
 18	 5:3	 1.667	 1.406
 19	 7:4	 1.750	 1.452
 20	 9:5	 1.800	 1.480
 21	 2:1	 2.000	 1.587
 22	 9:4	 2.250	 1.717
 23	 7:3	 2.333	 1.759
 24	 5:2	 2.500	 1.842
 25	 8:3	 2.667	 1.923
 26	 3:1	 3.000	 2.080
 27	10:3	 3.333	 2.231
 28	 7:2	 3.500	 2.305
 29	 4:1	 4.000	 2.520
 30	 9:2	 4.500	 2.726
 31	 5:1	 5.000	 2.924
 32	 6:1	 6.000	 3.302
 33	 7:1	 7.000	 3.659
 34	 8:1	 8.000	 4.000
 35	 9:1	 9.000	 4.327
 36	10:1	10.000	 4.642

o "Prat" is the ratio between the periods of two adjacent orbits (Outer:Inner).
o "Pmux" is the multiplier applied to the period inner orbit to determine the period of the outer orbit
o "Rmux" is the multiplier applied to Orbit 0 to determine the radius of Orbit 1. This is the only time this column is used.

Assumptions & Knowns:

• P^2 = R^3
• R = (P^2)^(1/3)
• P = (R^3)^(1/2)

o Unavailable (UA) orbits are subject to intense heat from the central star and have temperatures of greater thsn 2000 degrees. The "Rock Line" orbit is the outermost Unavailable orbit.

o Inner Zone (IZ) orbits expose worlds to too much stellar radiation; such worlds are hot, dry, and generally inhospitable.

o Habitable Zone (HZ) orbits are in a temperate region where stellar rsdiation is neither too much nor too little. If other factors are right, llfe may exist on worlds in this region.

o Outer Zone (OZ) orbits do not provide enough stellar radiation for worlds; such worlds are cold and inhospitable.

o One "standard" day is 24 hours long.
• Or 1,440 minutes long.
• Or 86,400 seconds long.

o One "standard" year is 365.2421875 days long.
• 365 and 31/128 days long.
• 365 days, 5 hours, 48 minutes, 45 seconds long (365:05:48:45).
• Also called the "Mean Solar Year" or the "Mean Tropical Year".
• This is a real-world value.

o Single-star stellar system.
• Needs work-up for multi-star systems.

o Spectral Class of star is known
• For this discussion, use "G2".
• If Spectral Class is M0 through M9, Size DM for all planets is -2.

o Luminosity, relative to Sol, is known
• For this discussion, use "1"

o "Rock Line" orbit is known (0.300AU)
• A planet in this orbit would be vaporized and dissipated.
• Part of Inner Zone (IZ).
• This orbit cannot be occupied by a planet.

o Inner Zone (IZ) is known (>0.300AU to <0.707AU)
• DM for SIZ is -2 per orbit inward from HZ.
• For all IZ orbits, DM for ATM is -2.
• For all IZ orbits, HYD is 0 (e.g., "Desert World").
• For all IZ orbits, DM for POP is -5.

o Habitable Zone is known (0.707AU to 1.414AU)
• If ATM is 0, 1, or A+, then DM for HYD is -4.

o Outer Zone is known (>1.414AU)
• For all OZ orbits, planetary DM for ATM is -4.
• If orbit is OZ+2 or more, roll 2D for 12 for ATM to be A (e.g., "Exotic").
• If ATM is not 0, 5, 6, or 8, then DM for POP is -2.
• For all OZ orbits, DM for HYD is -2.
• For all OZ orbits, DM for POP is -3.
• If ATM is 0, 1, or A+, then DM for HYD is -4.

o "Frost Line" orbit is known (3.000AU)
• "Frost Line" orbit is part of Outer Zone (OZ).
• Beyond this orbit, there be Gas Giants (GGs).
• Roll 2D for 5+ for each orbit beyond the "Frost Line" to have a Gas Giant.

Procedure:

A) Position orbits around central star.

1) Roll 2D to determine number of planets orbiting central star.
o If star Spectral Class is M0 through M9, apply a DM of -4.
o If star Spectral Class is K0 through K9, apply a DM of -2.

2) Determine radius of "Orbit 0 / Rock Line" in AU from Luminosity of star (1).
o 0.300AU = Radius of "Orbit 0" for G2-V star.
• Note: This orbit is "Unavailable, and therefore empty.

3) Determine period of "Orbit 0" in years from radius of "Orbit 0".
o (0.300^3)^(1/2) = 0.164yr (59.90 days) = Period of "Orbit 0"
• Note: This orbit is "Unavailable, and therefore empty.

4) Roll 6D to determine period multiplier (Pmux) of next orbit outward.
o Example: 6D --> 21
• Note: This example yields 2.000 for Pmux.

5) Multiply period of "Orbit 0" by Pmux to obtain period of "Orbit 1"
o 0.164yr x 2.000 = 0.328yr = 119.8 days.

6) Determine radius of "Orbit 1" from period of "Orbit 1"
o (0.328^2)^(1/3) = 0.476AU.
• Note: This example of Orbit 1 is in the Inner Zone (HZ).

7) Roll 6D to determine period multiplier (Pmux) of next orbit outward.
o Example: 6D --> 28
• Note: This example yields 3.500 for Pmux.

8) Multiply period of "Orbit 1" by Pmux to obtain period of "Orbit 2"
o 0.328yr x 3.500 = 1.148yr = 419.3 days.

9) Determine radius of "Orbit 2" from period of "Orbit 2"
o (1.148^2)^(1/3) = 1.096AU.
• Note: This example of Orbit 2 is in the Habitable Zone (HZ).

10) Repeat steps 6, 7, and 8, for each subsequent orbit.
o Pmux rolls: 21, 28, 19, 26, 18, 24, 20, 20, 24, and 19.
• Prat results: 2:1, 7:2, 7:4, 3:1, 5:3, 5:2, 9:5, 9:5, 5:2, and 7:4.

(continued)

 

[Keklas Rekobah]

From the above, I rolled a system of 10 worlds around G2-V star.

SYSTEM RESULTS

Orb:	AU:	YR:	Typ:	UWP:

  *	0.000	0.000	----	G2-V

  0	.3000	.1643	IZ-2	Empty Orbit ("Rock Line")

  1	.4762	.3286	IZ-0	G400364-8  -  Cy Lo Va -- --  A722

  2	1.098	1.150	HZMW	B956843-B  S  Ag -- -- -- --  G822

  3	1.594	2.013	OZ+0	F431464-8  -  Cy Ni Po -- --  A422

  4	3.316	6.039	OZ+1	Y000000-0  -  As -- -- -- --  A022

  5	4.661	10.06	OZ+2	Y000000-0  -  As -- -- -- --  A022

  6	8.587	25.16	OZ+3	LGG

  7	12.71	45.29	OZ+4	Empty Orbit (a few cometary bodies)

  8	18.80	81.52	OZ+5	SGG

  9	34.63	203.8	OZ+6	G502364-8  -  An Cy Ic Na Va  A522

 10	50.29	356.7	OZ+7	X402000-0  -  Ba Ic Va -- --  R022

NOTES:

The primary is a solitary G2-V star, similar to Sol.

Orbit 0 is the "Rock Line" orbit - the outermost of the "Unavailable" orbits, subject to intense heat from the central star. Any objects in this orbit would be turned to liquid and then sprayed out to the rest of the system by stellar winds.

Orbit 1 is occupied by a small, tide-locked world that is rich in heavy metals. A mining operation of about 7,000 people operates along the boundary between the light and dark sides. This world takes ~120.0 standard days to complete one orbit.

Orbit 2 is inside the Habitable Zone. The global population is about 8 hundred-million sophonts. The good-quality Class-B starport provides refined and unrefined fuel, overhaul facilities, and shipyards for constructing non-starships. There is a Travellers' Aid Society hostel within the extrality zone, adjacent to the main terminal. Although the culture is an agrarian one, with most of the citizens "living close to the land", there is enough industry to build and maintain farm equipment and support the local infrastructure. The environment is carefully maintained, and several large regions are off-limits to commercial development of any kind, including farming. This world takes ~420.0 standard days, or 1 year and ~55 standard day to complete one orbit.

Orbit 3 is occupied by a small, cold world. A network of a half-dozen domed and underground colonies has a long way to go toward self-sufficiency. The global population is about 40,000 sophonts, mostly scientists, engineers, and academics. This world takes 2 standard years and ~4.75 standard days to complete one orbit.

Orbits 4 and 5 are the inner and outer boundaries of this system's Planetoid Belt, 1.345 A.U. wide. In between these boundaries orbit uncounted numbers of irregularly-shaped objects less than 100 km across. Objects closer to the primary are mostly carbonaceous, while objects father out are mostly ices. There are several "Kirkwood Gaps" at harmonic intervals related to the LGG's orbital period. Objects in this asteroid belt take from ~6 to ~10 years to complete one orbit.

Orbit 6 contains a large gas giant (LGG), similar to Jupiter in the Sol system. It rotates about half as fast, so the atmospheric banding is less pronounced, and the radiation belts are less intense. The LGG has a ring system and over a dozen moons that are observable from the mainworld through moderately-powered telescopes. This world takes 25 standard years and ~58.4 standard days to complete one orbit.

Orbit 7 contains few, if any objects, due to the gravitational effects of both gas giants. Those objects that do orbit here are less than 1km across, and seem to be "Dirty Snowballs" reminiscent of cometary nuclei. Since this orbit is practically empty, it is listed as such.

Orbit 8 is occupied by a small gas giant that is a deep, sapphire blue in color, with little variation or recognizable weather patterns. The SGG has about a dozen known moons and a ring system. This world takes 81 standard years and 190 standard days to complete one orbit.

Orbit 9 is occupied by an ice-world that is also a "Die-Back" or "Ghost" world. A team of about 5000 archeologists and engineers are carefully excavating ruins that pre-date the arrival of the colonists from Terra by at least several thousand years. This world takes 203 standard years and 292 standard days to complete one orbit.

Orbit 10 is occupied by another ice-world. Several large craters are evident from orbit, and robot landers have detected the decay products of plutonium in and around the craters. Based on the size of the craters and the relative percentages of the decay products, it is estimated that the planet underwent nuclear bombardment sometime during the Ancients' Final War some 300,000 years ago. The world is a RED TRAVEL ZONE due to the radiation hazard. This world takes 356 standard years and 256 standard days to complete one orbit.

Questions?

 

[aramis]

Way too much work for way too little gain.

 

[Gray Lensman]

I have used LBB 6, WBH, Gurps Space, and 2300 in the past and at times have mish-mashed things like using Gurps then adding detail stuff from WBH, Heaven and Earth was great to but sadly I am stuck with a stinking chromebook for the foreseeable future

 

[Keklas Rekobah]

I have used LBB 6, WBH, Gurps Space, and 2300 in the past and at times have mish-mashed things like using Gurps then adding detail stuff from WBH, Heaven and Earth was great to but sadly ...

That's why I'm starting from scratch, and building on Real World Science. For instance ...

... Orbital Resonance. The Titius-Bode Law is a mere coincidence that works in only one known instance; and even then, it works only part of the time. Thus, it has been debunked. The number of orbits completed in the same time interval by two adjacent worlds is more likely to be a close integer ratio; such as 2:3, where the outer world completes 2 orbits in the time that it takes the inner world to complete 3 orbits. This has been observed to be true in several stellar systems, including our own.

... Rock Line: This is the innermost orbit at which a planet might exist in a solid state. Any closer to the star it orbits, and it will become molten, and likely sublimate as the stellar winds drive a steady mist of molten material into the outer system. This orbit is also called the "Lava Line" (I refer to it as "Orbit Zero"), and has a radius in our solar system of about 0.3 A.U.

... Frost Line: This is the orbit that marks a boundary between terrestrial planets and gas giants. Inside this orbit, planets tend to be rocky, metallic, and likely to have liquid or gaseous water. Outside this orbit, solid water tends to accumulate; either on solid surfaces, or into isolated clumps, ans planets tend to be either ice-covered rock balls or enormous gas giants. This orbit has a radius of about 3.0 A.U. in our solar system.

... Inverse-Square Law: The intensity of radiant energy per unit area is inversely proportional to the square of the distance from the source of that energy. Thus, our sun would provide only about 11% of the energy to an Earth-sized planet at the "Frost Line" orbit than it does to Earth, and over 1100 times the energy to a hypothetical Earth-sized planet at the "Rock Line" orbit. From this, and knowing the luminosity of a star in another system, it is easy to determine the "Rock Line", "Frost Line", and "Habitable Zone" orbits for that other system.

Too much work? That's what computers are for ...

 

[ShawnDriscoll]

Too much work? That's what computers are for ...

Yes. Computers are good at generating all the fluff that players are not really all that interested in. Makes for nice diagrams displayed in the background, or on Referee screens.

 

[aramis]

.

Too much work? That's what computers are for ...

When the game cannot be run without a computer, it is time for a better game.
Traveller is, at MT, as complex as I can run analog. I don't even like using Travellermap.com in session, as it encourages players to use phones in session. And that is too much distraction already.

 

[sfchbryan]

When the game cannot be run without a computer, it is time for a better game.
Traveller is, at MT, as complex as I can run analog.

But it isn't being run at the session - it is done by the GM offline, while preparing an adventure.

A computer isn't mandatory, but it can make things easier. I have a Bento database with every Library Data entry I have acquired, plus my campaign material. I make it available for both the players and myself.

It is much better than having the PCs look at the Imperial Encyclopedia, because I can subtly change info in it. The OTU becomes MTU.

 

[Ulsyus]

Way too much work for way too little gain.

Seconded.

When the game cannot be run without a computer, it is time for a better game.

Yeah. We may all use computers to prepare for games, to develop game aids, to run calculations to develop flavour for what we're doing, but for some of us the outcome is the main thing.

That said, if you get a lot of fun out of this sort of thing, then go for it. If it's necessary in YTU then go for it. Just be okay with some people scratching their heads at the detail you develop.

 

[Keklas Rekobah]

Seeing as how I worked 6 years in the USN, 5+ years to earn an MSEE, 4+ years as an instrumentation engineer in the astronomy department of a mid-western university, and then experienced two heart attacks and a divorce, I can certainly understand the idea of "To Much Work / Too Few Rewards"...

... But I see developing a reality-based method of simulating stellar systems as a challenge, and not a show-stopper. So, all philosophical objections aside, I'm going to finish this project. Whether or not it proves profitable for me will then be solely to my own credit.

 

[aramis]

But it isn't being run at the session - it is done by the GM offline, while preparing an adventure.

Most of my setting development is done on the fly, in game during session, because i suddenly need the details.

I seldom have the luxury of traveller players who will follow a scripted adventure, or even a route.

 

[Higgipedia]

I've gotten a lot of mileage out of the RTT Worldgen system. It is vague enough with distances and calculations to suit my fancy. You can whip up a system fairly quickly and individual planets even quicker.

 

[Enoki]

My problems with the generation system revolve more around the people and politics of the resulting system than the planets and satellites themselves. Sure, the later might not be as close to scientifically accurate as we know today, but it's generally good enough.

But, I see the roll up for secondary planets, population, government, law level, TL, as being sort of an afterthought rather than really going well with the system and home world in general.

For example, as the main world's population and TL increase I'd think the likelihood is that the rest of the system's planets and satellites start to get filled up too.

I also think given the ship travel times intra-system being days to weeks, particularly if there's outlying planets, that some of these more isolated ones and even gas giants with numerous occupied satellites would form secondary governments and worlds that might only be tenuously attached to the main world.

I also think that in such systems more than one star port is possible with just the "best" or most used one being on the overall UPC.

As an example of that, what if you had a system with two groups of such planets and there were having a civil war between them? That's certainly possible.

On the whole I think this part of system generation needs more work to make more possibilities within a system available. It would make for games and scenarios where the players have a lot to do in the system they're in and for less need to go to other systems.

 

[Ulsyus]

But, I see the roll up for secondary planets, population, government, law level, TL, as being sort of an afterthought rather than really going well with the system and home world in general.
...
I also think that in such systems more than one star port is possible with just the "best" or most used one being on the overall UPC.

Good points. I always understood the system generation model to be one that provides details on the primary planet. If there's not much on it, then there may not be much else in the system. But that doesn't preclude, in a more heavily populated system, to have a mainworld that's heavily populated with a couple of other planets in the system having similar, but lesser number, of sophonts there. The main thing is that the listed world is the main game in that system.

 

[khadaji2002]

My problems with the generation system revolve more around the people and politics of the resulting system than the planets and satellites themselves. Sure, the later might not be as close to scientifically accurate as we know today, but it's generally good enough.

But, I see the roll up for secondary planets, population, government, law level, TL, as being sort of an afterthought rather than really going well with the system and home world in general.

For example, as the main world's population and TL increase I'd think the likelihood is that the rest of the system's planets and satellites start to get filled up too.

I also think given the ship travel times intra-system being days to weeks, particularly if there's outlying planets, that some of these more isolated ones and even gas giants with numerous occupied satellites would form secondary governments and worlds that might only be tenuously attached to the main world.

I also think that in such systems more than one star port is possible with just the "best" or most used one being on the overall UPC.

As an example of that, what if you had a system with two groups of such planets and there were having a civil war between them? That's certainly possible.

On the whole I think this part of system generation needs more work to make more possibilities within a system available. It would make for games and scenarios where the players have a lot to do in the system they're in and for less need to go to other systems.

I like this idea. I would enjoy having the means to develop a system for the players to start in that is more complex than what the dice allow for right now. Granted, I can hand-wave anything for a given star system. Having rules from Traveller to offer suggestions would be grand!