Welcome! These forums will be deactivated by the end of this year. The conversation continues in a new morph over on Discord! Please join us there for a more active conversation and the occasional opportunity to ask developers questions directly! Go to the PS+ Discord Server.

A Chart for Randomly Generating Planets

12 posts / 0 new
Last post
Thampsan Thampsan's picture
A Chart for Randomly Generating Planets
Looking for input and tweaking. Note all planetary type references are gratuitously borrowed from the Orions Arm project (you guys rule; Anders et al). Exoplanets Planet Type (gate-world) 1-3 Arean Xeric (Hot dry martian world) 4-7 EoArean (Young martian world) 8-11 Arean Tundral (frozen martian world) 12-15 Arean Lacustric (More mature young martian world) 16-19 EuArean (Mars-like world) 20-22 Artificial World (roll again, exclude doubles of this result) 23 TITAN World (Synthetic world) 24 Dyson Sphere (roll again, exclude doubles of this result) 25-29 Asteroid 30-31 BathyPelagic (Gaian type world, deep oceans 85-100% water coverage) 32-35 Campian (Gaian world <50% water coverage) 36-39 Cerean (small rocky planetoid) 40-43 Chlorine (Gaian world with high atmospheric chlorine) 44-47 Cthonian (remnants of gas-giants with no atmosphere) 48-51 Cytherean (hot green-house worlds) 52-53 EuCytherean (boiling green-house worlds) 54-57 European (rocky core, thick ice mantle and crust) 58-59 Ferrinian (80%+ metal core and siderite minerals) 60-62 Gaian 63-66 Gaian Tundral 67-69 Hadean (planetoid of mostly metals found near stars) 70-72 Hermian (dense inner system worlds) 73-74 Hyperbarian (super-dense core worlds with many Gs) 75-77 Ikarian (errentic orbit worlds) (roll again, exclude doubles of this result) 78-80 Panthalassic (super-terrestial waterworlds) 81-84 Selenian (little or no metallic core worlds) 85-87 Skolian (large axial tilt worlds) (roll again, exclude doubles of this result) 88-89 Stevensonian (interstellar worlds) (roll again, exclude doubles of this result) 90-92 Superterrestial 93-94 Titanian (icy world with thick atmosphere) 95 To'ul'hian (high pressure gaian world with super-dense atmosphere) 96-98 Vesperian (tidally locked worlds) (roll again, exclude doubles of this result) 99 Vitriolic (highly acidic worlds) 100 Ymirian (worlds made almost entirely of ice) Type of Star (number of stars equals 1d10/2, option on 10 for unmodified dice roll) 1 Blue 2 Blue-White 3 White 4 Yellowish-White 5 Yellow 6 Orange 7 Red 8 Purple-Red 9 Brown 10 Dark Brown Notable Planet Features (1d10/2) 1-2 Life (naturally occurring) (Roll d100, if 00-05 Intelligent) 3-4 Life (artificially created/seeded) (Roll d100, if 00-05 Intelligent) 5-6 Transhuman Settlement (00-30 Inhabited, 31-70 Abandoned, 71-99 Destroyed) 7-8 Post-Human/Ex-Human Settlement (00-35 Inhabited, 36-70 Abandoned, 71-99 Destroyed) 9-11 Interesting Natural Phenomena 12-15 Sculpted terrain 16-20 Wild/spectacular naturally occurring terrain 21-41 42-43 Alien artefacts (trivial) 44-45 Alien artefacts (significant) 46-47 Alien structures (small) (00-80 Safe, 81-99 Dangerous) 48 Alien structures (large) (00-60 Safe, 61-99 Dangerous) 49 Alien megastructure (00-60 Safe, 61-99 Dangerous) 50-53 Easily accessed exploitable resources 54-56 Exploitable resources, difficult terrain 57-59 TITAN remnants 60-75 Natural phenomenon (hindering) 76-85 Natural phenomenon (very dangerous/frequent) 86-95 Cosmic phenomenon (dangerous!) 96-97 Archaeological dream site (00-75 Safe, 76-99 Dangerous) 98 Cache of supplies left by other gatecrashers (00-65 Safe, 66-99 Dangerous) 99-00 Roll again twice (ignore doubles of this result) Gate Use (roll after successful activation, never roll on crit-successes) 00-50 Activates as specified, dials address and connects 51-60 Activates, dials address, loses connection 61-70 Dials but returns error, cannot find address 71-80 Dials random address 81-85 De-activates and locks down for (00-70 1d10 hrs, 71-90 1d10 days, 91-00 1d10 weeks) 86-90 Activates, dials but transportation through results in scrambling (00-40 Inorganic Material Only, 41-80 Organic Material Only, 81-99 Both/All) 91-95 Activates, dials but transportation through will result in sentients being uploaded (00-40 Not uploaded but copied, 41-80 Uploaded never emerges, 81-99 Replaced) 96-99 Activates, dials but target gate begins working off a new directory for 1d10 hrs. Old address won't dial back to planets they connected to before, etc.
Arenamontanus Arenamontanus's picture
While this table is great for
While this table is great for getting cool adventure locations, I think it uses a too flat distribution. For example, the vast majority of stars are red dwarves and blue stars are rare. And chlorine worlds are probably far rarer than gaian worlds! When playing with http://www.eldacur.com/~brons/NerdCorner/StarGen/StarGen.html you typically get mostly gas giants and small, cold planets (like in the solar system). Of course, that program was likely written before the sheer weirdness of exoplanets started to grow. In the end, I suspect the main use here is not "realism" but to quickly generate something where people jump through gates - that is *very* useful, and I will probably use it rather than StarGen next time I run gatecrashing.
Extropian
Thampsan Thampsan's picture
Yes, statistical modelling is
Yes, statistical modelling is not one of my strong points. I welcome people to alter it or even build a generator from it that might tailor better to more realistic planet/solar system distribution. I also struggled with a way to take into account odd phenomenon like multiple gates in a solar system, or on the same planet, or generating an entire solar system. But now having seen the generator you linked, I am awed. It is incredible, I shall be using that extensively to give my Gatecrashing a more credible feel when it comes to describing air, gravity, atmospheric content, etc. Cheers for the amazing link Arenamontanus.
thelabmonkey thelabmonkey's picture
I wonder if splitting the
I wonder if splitting the first list into 4x categories in order to allow for better distribution of likely planets within that category... so pick a planet "type" as a GM, or even roll on a table-table to see which table you look up! Table-Table - weighted in favor of player "friendly" destinations... 1-2: Extreme - meteor, asteroid, no/poison/acid atmo, extreme temps 3-5: Inhospitable - rocky, frozen, etc 6-9: Hospitable - Maybe still need a vac-suit, but not as intrinsically deadly as boiling lava-covered vacuum moon? 10 (or 0) OTHER - Zany things like dyson spheres or planet sized computers then you can have a wider distribution of numbers to adjust roll outcome on those individual tables...
Undocking Undocking's picture
The following link is for a
The following link is for a very extensive guide to generating solar systems: Star System Creation Guide I used it extensively for Rogue Trader and another GM in my group used it as a basis for his Prussianesque space opera game.
Arenamontanus Arenamontanus's picture
That creation guide was
That creation guide was pretty neat. Only glaring fudge is the surface gravity calculation. It looks like it would be very useful and modern. I grew up using the 2300AD system creation rules. It is much more physics based, but for most practical game purposes this doesn't matter much (except to make you feel you are doing hard sf - this is the only rpg system where you have to calculate a cube root). I even did some statistics on the frequency distribution of planet types it made: http://www.flickr.com/photos/arenamontanus/2420915580/ There is of course an important difference between a star system generator and a planet generator: the first makes a set of planets and makes sure they have the right relations. In ongoing games you typically need random planets, but when planning a setting systems are better.
Extropian
Thampsan Thampsan's picture
Regarding my original
Regarding my original starting post, but perhaps I could crowd source good ideas for types of planetary hazard, both natural (hindering and dangerous) and cosmic. The chart doesn't take into consideration hazards generated by the type of planet (i.e toxic atmosphere or high gravity) so some planets automatically get one of more of those traits just by existing, but if they roll them again what sort of things could we add. * Earthquakes * Severe Weather Phenomenon (storms, hurricanes, acid/boiling rain, etc) * Sinkholes * Volcanic activity * Geysers * Irregular toxic emissions * Highly irradiated If people could suggest more I would be greatly appreciative.
Thampsan Thampsan's picture
To give everyone an example
To give everyone an example of my chart in action here is a planet that I built a game around. Discipline System Blasted Wasteland (Hermian, Dense Inner System World) Longdead (Brown Dwarf) The Hermian world has no atmosphere (and reaches a frigid -200'C during it's night cycle) and the gate site is located within one of many deep craters that scar the planet. A cluster of fragments from a moon, or several moons orbit this world and as the planet swings in close to it's star every few cycles the gravity pulls more of these fragments into the planet. The planet is 60% of the size of Venus and has a gravity of 0.7G. Lacking an atmosphere and bathed in radiation from the dying star make this planet dangerous to those who lack good shielding. Of interest on the world is it's nature, only a thin layer of rocky substrate covers a large, mostly cool core and the heavy metals beneath the surface. In one place not even that, and the planet's current close orbit can likely be attributed to a massive collision that has opened up the planet and has led to common earthquakes that shake the surface. It is known that other visitors have come to this world as scattered at random around are small polyhedrons made of non-reflective metamaterial that fluoresces under certain radiation, they can be seen (difficult check) in orbit around the world under the right circumstances and though they have no immediately visible purpose, are in fact alien probes/satellites. Academics: Xenotechnology or something similar will determine that each small (2cm) polyhedron are highly compact QE devices, 97% of them have nothing left and only those that have entangled electrons actual have any programming left, all other self-delete and become more debris. Somewhere in the dust belt around the planet are a series of now mostly ruined factories designed to building more of these. Even if these could be reached they too have self-wiped due to damage and can no longer contribute useful information on the production of entangled electrons in these states. More interestingly is that there are craters on the world not caused by asteroid impacts and the truth of the matter is that within the remnants of the solar system long dormant alien weapon systems are trained on the world and it's gate occasionally slagging it. While the bulk of these are inactive/dead all are so well hidden that only with years of combing through the dangerous system might one find these. In essence the planet serves as both a testing ground and is quarentined. Out of interest the weapons trained on the planet are largely advanced mass driver factories (most are the size of small asteroids) that process the ambient dust and debris they pass through in their highly erratic orbits form them into charged material and launch them at the world. For reference the system is in a distant section of the galaxy, in one of the inner arms. Notes on player interaction; Feedstock for replicators is plentiful (24hrs to acquire bulk of material) Satellites orbiting suffer heavy interferrence from the heavy radiation of the dying star Satellites also risk being bought down by the heavy orbital swarm of meteorites and charged dust Radiation Shielding required, organic morphs not in cover of a heavy vehicle with shielding will perish after 72hrs of constant exposure. World is occasionally visited by Exsurgents (wearing synth shell ranging between 3m and 4m in height, with multiple rotating disks about 30cm thick. These vertical segments are irregular in shape and some layers can manifest grappling limbs, weapons, etc. Primary form of movement is hovering, but walker-limbs can manifest on top or bottom. The Ziggynaut Exsurgents are largeless harmless unless confronted or disturbed, each Ziggynaut layer is a different personality. Armour 14/14, WT 15, DR 120). Hermian (Dense inner system world), 1 sun (Dark Brown), Alien artefacts (trivial), Cosmic phenomenon (dangerous!), Interesting Natural Phenomena Alternatively here is another; Pandora System Pandora's Ark (Asteroid) Pandora (Red Giant) This asteroid in the main belt of a Red Giant not too distant to our own contains two gates and a large gate complex. The address is especially difficult to dial and more often than not results in an error and emergency shut down, gates that do open are prone to terminating unexpectly or causing other horrific consequences. This complex is made entirely of the same organic metal that comprises the gates and so poses a psychological hazard. The winding corridors are devoid of much in the way of technological remnants and only trace organic residue. Inhabiting the facility was a post-human clade descended from an Ultimate research collective led by one Adolph Schraebler. The clade having successful led many gatecrashing missions and recovered many significant alien technologies stumbled onto the remnants of a second gate that was partially started but left abandoned, though the remnants looked like TITAN or at least exsurgent infected the clade dedicated a lot of time to researching this. Over a period of years they severed ties to the Ultimates, the split was not mutual and the clade used their knowledge of gatecrashing and research to thwart hostile attempts at reintegration. Once alone they began radically altering themselves in ways that would allow them to better understand and manipulate molecular structures. From this they created the 'Schraebler Morph', in it's early forms the result was a remade body that ran hot but was optimised for inuitive identification of molecular structures. Over a series of rapidly grown generations the morph became more an more alien blurring the line between organic and cybernetic, but also human and alien. The latest iteration of the bodies stands between 2 to 2.5m tall, an appear as large, bipedal insectoids with a thick chameleonic carapace exoskeleton. The head contains no orifices, save for highly modified tear ducts and two giant compound eyes that take up the bulk of the head. Their torso is roughly trapezoidal in shape and holds four arms with multi joined limbs and fine manipulatory digits that can manifest fractal tools or claws for defence and digging if need be. The bain of the Schraebler Morph is a decentralised nervous system as much contained within the spongy, flexible 'bone structure' as within a nerve/brain cluster distributed through the lower torso. All breathing and nutrient consumption is conducted via nutrient tubes located in the arm pits and each morph is dependent on this for survival as they contain no stomach and limited ability to store reserves of 'fat' or 'air'. Similar 'access' ports exist for uploading and resleeving purposes. All morphs are vacuum adapted and can put themselves into a state of hibernation if required. All Schraebler Morphs designed for low-gravity, low temperature environments and are prone to over-heating and severe stress on bodies with a gravity of greater than 0.6G. These most recent bodies are too alien for normal transhumans to inhabit as their sensory suit is so complex and requires an understanding of molecular structures far in excess of current thinking, but also because they lack any sort of frame of reference being in the Schraebler Morph will drive them mad within a matter of hours. Communication within the new post-human clade is done largely via mesh, but if need be members of the clade can use their chameleonic exoskeleton to communicate in a manner not dissimilar to the way octopi communicate natively. Asteroid, 4 Stars (White, Yellow, Red, Red), 4 Traits (Archaeological Dream Site – Dangerous, Exploitable Resource – difficult, Post Human Outpost – Abandoned, Cosmic Phenomenon – Dangerous, Sculpted Terrain)
bibliophile20 bibliophile20's picture
Did some work on creating my
Did some work on creating my own gatecrashing planet generator; this topic was certainly useful for inspiration for some of the tables. Thanks for the links and to the OP! https://docs.google.com/document/d/1P5fKuU_8Wkgiw96LHNCJwroryXCBZdJ2HaCy...
Spoiler: Highlight to view
GM Note: Due to first-in protocols and the sensor probe first sent in to assess the viability of a given gate location, this table will be skewed towards transhuman-survivable locations. The only times when the probe isn’t sent through first is in emergencies, and then the resulting location is often more for the benefit of the story that the GM is telling. Location, Location, Location GM Note: Due to first-in protocols and the sensor probe first sent in to assess the viability of a given gate location, this table will be skewed towards transhuman-survivable locations. The only times when the probe isn’t sent through first is in emergencies, and then the resulting location is often more for the benefit of the story that the GM is telling. Location, Location, Location Table 1-1: Conditions on the other side d% roll Result 01-33 Extreme--Heat, Cold, Pressure, Radiation, etc; survivable, but only with specialty gear 34-66 Inhospitable--Survivable, but hardly a walk in the park 67-99 Benign--While a flat is not capable of surviving unassisted, transhumanity has colonized far worse. 100 Habitable--atmosphere at pressures and temperatures a flat or splicer can tolerate (perhaps even oxygenated!) The Star System System Components d% roll Star System 01-60 Single star 61-90 Binary stars 91-100 Multiple stars Table 2-2: Stellar Classification d% roll Stellar Class 01-45 M (Red Dwarf) 46-79 K (Orange Dwarf) 80-94 G (Yellow Dwarf) 95-96 F 97 A 98 B 99 O 100 Other (White dwarf, brown dwarf, rogue planet, neutron star, black hole, etc) Table 2-3: Other System Components d% roll Result 01-10 Not much here; the star(s), some asteroids, not much else. 11-45 One significant planetary body, maybe some moons and asteroids. 46-70 2-5 significant planetary bodies, significant smaller bodies 71-99 6-20+ significant bodies, swarms of smaller bodies 100 Other (Dyson Sphere, Global Cassus, Gas torus, giant space stations, etc) Table 2-4: Assorted Debris d% roll Planet Type 01-55 Terrestrial (roll on Table 2-5) 56-100 Gas Giants (roll on Table 2-6) Table 2-5: Small Little Rocks d% roll Planetary Type 01-10 Rocky Mesoplanet (dwarf planet or planetoid), internally differentiated 11-20 Terrestrial, Rocky (Mercurian) 21-25 Terrestrial, Desert (Mars, et al) 26-30 Terrestrial, Marginal (more habitable Mars) 31-40 Terrestrial, Hostile (Venusian) 41-42 Terrestrial, Oceanic 43-44 Terrestrial, Glaciated 45-49 Terrestrial, Reducing (Chlorine, Fluorine, etc) 50 Terrestrial, Earth-like 51-54 Terrestrial, Greenhouse 55-60 Terrestrial, Carbide (carbon-rich, oxygen-poor) 61-75 Terrestrial, Chthonian (Exposed core of a former gas giant) 76-80 Terrestrial, Coreless (No metallic core) 81-100 Icy Mesoplanet (Europa, Ganymede, Titan) Table 2-6: Big Bags Of Gas roll 1d10 to determine relative distance to primary; 1: sunskimmer, 2-4: habitable zone, 0: Neptunian-type orbit. Also, typically, the further out and larger a gas giant is, the more moons it has, with distance to the primary having greater influence. For determining moon characteristics, note distance to primary and act accordingly. d% roll Planetary Type 01-10 Small Neptunian (3-10 earth masses) 11-25 Medium Neptunian (10-20 earth masses) 26-40 Large Neptunian (20-50 earth masses) 41-55 Small Jovian (51-150 earth masses) 56-65 Medium Jovian (150-300 earth masses) 66-80 Jovian (1-3 jupiter masses) 81-90 Large Jovian (4-15 jupiter masses) 91-99 Super Jovian (15-45 jupiter masses) 100 Brown Dwarf (45-85 jupiter masses) Table 2-7 Shiny, Interesting Things: roll 1d10 (treat 0 as zero) d% roll Notable System Features 01-25 Economically Exploitable Resources 26-35 Interesting Natural Phenomena 36-45 Dangerous Natural Phenomena 46-55 Impressive Natural Terrain 56-65 Dangerous Natural Terrain 66-70 Alien Archeological Remnants 71-79 Alien Sky (Nebula, Galactic Rim, Stellar Cluster, etc) 80-84 TITAN Remnants 85-90 Alien Life 91 Gatecrasher Supply Cache 91-94 Transhuman Settlement 95-97 Post-Human/Ex-Human Settlement 98 Multiple Gates 99 Roll again twice. 100 Roll again three times. Table 2- Oddballs (Optional) d% roll Characteristic 01-15 Highly eccentric orbit 16-30 extreme axial tilt 31-45 extremely long days 46-60 extremely short days 61-65 binary planet 66-80 tidally locked 81-85 significant body occupying Lagrange point(s) 85-99 Extreme orbital inclination 100 physics anomaly

"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -Benjamin Franklin

Arenamontanus Arenamontanus's picture
I just found a fascinating
I just found a fascinating presentation about simulating the formation of planetary systems: http://www.mpia-hd.mpg.de/~mordasini/slidesws1123/L15popsynth.pdf The thing to look for is the PIMF (Planetary Intitial Mass Function) on page 15, showing the distribution of planet masses - they seem to form a few nice bumps, so one could likely model this by rolling for overall type on a table and then rolling a size (in such a way you get a normal distribution). Their probability estimate of the size is: (Super)-Earths (<7 earths) are 58% Neptunians (7-30 Earths) 17% Intermediate (30-100) 6% Jovians (100-1000) 14% Super-Jupiters (>1000) 4% Page 13 has a very neat diagram showing the distribution of planetary orbits and masses: I would love to figure out how to roll on this with dice. The obvious method is to divide it into a matrix, give each cell a measure based on planet density, and then linearize it into a cumulative table, but it would be nice with a smarter approach. His site also has interesting work on planet formation - young gas giants are *enormous* fluffy things for about a million years before quickly shaping up. They cool exponentially (any moons habitable because of just the giant will have had a long period of being too hot), and the maximum diameter is about 30 Earth radii (for 1000 Earth masses) - above that the gas giant shrinks because it is really dense: super-Jupiters are smaller than Jupiter.
Extropian
Arenamontanus Arenamontanus's picture
An addendum: the slides from
An addendum: the slides from this conference http://www.mpia-hd.mpg.de/~mordasini/ringberg/talks.html also show various models of where planets end up... maybe. Plenty of abstruse astrophysics here. But check out slide 3 of http://www.mpia-hd.mpg.de/~mordasini/ringberg/lin.pdf or the first slide of http://www.mpia-hd.mpg.de/~mordasini/ringberg/ida2.pdf - these are likely the basic masses and locations to use, and based on that, some eccentricity data (another big debate in the slides) and the volatile levels one can then likely guesstimate planet properties.
Extropian
Thampsan Thampsan's picture
Just bumping this thread to
Just bumping this thread to bring it closer to more recent threads discussing similar exoplanet chart/creation topics. Cheers for the input by the way Arenamontanus.