Everything Wrong With BattleTech's Star System Generator - Vector-Graphics/walkersysgen GitHub Wiki
So I kind of have a unique connection to BattleTech, as I know some of the people behind the Battletech videogame published by Paradox. Regardless, the Battletech videogame is not the original Battletech tabletop game, which this generator is for, so let's get straight into it.
So, first of all, assumption that M-type stars can't support life! This is kinda weird, because it is very well possible that at least some M-type stars flare at the poles (which is what I choose to interpret that study as, as opposed to being a general statement about M stars). Additionally, any comments about uninhabitability of tidal locked planets are probably quite wrong. +1 (1)
Oh boy, this is gonna be good. "Orbital slots" almost never end well when they're generated like this. +1 (2)
Oh no, Bode's law! Absolutely the most accurate method for determining orbits, right? I mean, it's not like the entire planet Neptune exists! And the Trappist-1 system! +1 (3)
Also, this says to multiply the orbits by the star's mass instead of the square root luminosity. In fact, in main sequence stars, this is the 3.5th root luminosity! Mathematical inaccuracy!? In my solar system generator? +1 (4)
Okay, this does have habitable zones, but it's not quite as bad as you would think (mainly, it doesn't do the dumb 0.95 AU☉ thing). Despite this, it's still habitable zones, which unfairly favor the status of liquid water on planets over other factors related to temperature. +1 (5)
It does erroneously calculate the temperature at 0.66 AU☉ as around 308 Kelvin, when it should be 351 Kelvin (or around 80 C, the upper limit for a planet with an Earth-like atmosphere, unless you're brave enough). This does seem to imply that a planet getting hotter than around 35 C on average will render it uninhabitable, which, uh, no it won't. +1 (6)
Okay page 6 spends like the entire page waffling about "transit times". Hey, it at least uses my "distance from outer planet to star" approximation, which is nice.
Okay. So it goes through ALL THIS to calculate radii, densities, whatever, but STILL leaves out the critical feature of the planet's composition! Why is this so hard for generators to understand! You know what, here's a slight improvement. If it's less than 4 AU☉, it's rocky! If it's greater than 7 AU☉, it's icy! If it's somewhere in the middle, I don't know, flip a fucking coin! +1 (7)
Waaaaait, if there are unterplanets IN the asteroid belts, what the hell is that "dwarf terrestrial" column in the planet types? +1 (8) I mean, I know it's just a misunderstanding of Pluto's position relative to the Kuiper Belt, which actually makes it even worse. Fuck Pluto. +1 (9)
Okay, these tables are kind of notoriously hard to comprehend just by looking at them. For a while I thought there was a "Planet Type" index I missed somewhere that went from 1 to 6. But no, there's just a random die that you roll to determine what moon configuration a planet has. +1 (10) Which like, sure, but why is the precise size not used here? Why can the dinky 600km wide dwarf planet have a moon that's also 600km wide and literally more massive than it? +1 (11)
And now we go back to listing habitability as the first aspect of a planet worth mentioning. +1 (12)
Oh wow, go ahead, just assert that less than 1 in 1000 systems have a habitable planet IRL! It's not like there are perfectly valid models that predict more than that (even about 1 in 2 systems, hint hint nod nod wink wink). It's not like we literally don't know! It's not like the Solar System alone had 2 habitable planets less than a billion years ago! +1 (13)
Lol, "9 or better on 2d6". They're not even gonna say what the factor is here. This is just a blatant Rare Earth factor out in the open. At least when I make assertions I tend to explain them. +1 (14)
It's nitrogen. +1 (15)
I said, it's nitrogen.
Unless it's carbon dioxide, in which case it's carbon dioxide. Go ahead and tell me what planet we've seen with an atmosphere made of fricking ammonia.
Uninhabitable and habitable atmospheres are generated separately instead of, y'know, just being bundled in with that random 5/18 chance. +1 (16)
OK. Here goes the Habitable Planet Features table. It gets worse as you go on. But first, the fact that habitable planets have special features other than life. +1 (17)
Percent Surface Water. Why do so many generators feel the need to generate this? Just go with "small seas, world-continent, world-ocean, island-world, or ocean world" and be done with it. This doesn't generate climates, at least it doesn't seem to give anything beyond rough guidelines. +1 (18)
"Very High", you say? I read the page, and that's like, 45 Celsius! EQUATORIAL temperature! Earth is in the "high" range! I think it can basically get up to 85 Celsius there and still be "habitable" to some form of life planetwide, and even then that's assuming Earth's kind of atmosphere. +1 (19)
How the hell are atmosphere compositions LESS detailed here than on the non-habitable planets ? It does specify a nitrogen-oxygen atmosphere as a default, so I assume "tainted" refers to "nitrogen-oxygen with some Pollutant(tm) that needs to be filtered out unless you're brave enough", and "toxic" refers to plain nitrogen with maybe some other stuff. But still! The other generator SPECIFIED those trace elements! +1 (20)
I thought this one was the worst part of it, until I saw the next one.
HAHAHAHAHAHAHAHAHAHAHAHA HAHAHAHAHAHA okay wait HAHAHAHAHAHAHAHAHAHAHA Okay. Microbes, yeah, ok. Plants, I mean, I guess, I wouldn't really place an entire taxonomic kingdom on an arbitrary scale of "highest" life-form. But "insects"? "Fish"? "Amphibians"? "Reptiles"?? "Birds"?? "Mammals"?!? Again with the "highest life-form" bullstuff, and also with the linear development fallacy! Clades on an alien planet would NOT develop like this! +2 (22)
Okay, I read closer and it doesn't actually make this assertion in particular, instead using these groups as an analogy, but still does make the assertion that Earth clades have a linear progression to them to begin with. -1 (21)
At first I thought this was planetary biomes, but to be clear, it's not, each planet is divided into multiple climate zones, even though those are kind of dependent on the general temperature of the planet itself. But that little "native life" tag appears to assume, from my best inference, that planets are by default treated as extensions of Earth's biosphere, which is... NOT how that works! +1 (22)
mfw implied setting (well, makes sense, it is a Battletech system generator, but I've reviewed generators for settings I'm much less aware of as if they're setting-neutral, so I might as well be fair and sin this anyway. Also, it's never specified exactly how much exploration is "a thousand years", so I can't make a real judgment on if there's some ludicrous factor there. +1 (23)
Ignoring the implied setting here, why isn't incompatible biochemistry taken as a given? +1 (24)
Anyway, after this the main body of the generator is done, and the rest of it is just a giant wall of text for optional things that aren't important to the generator itself, so I feel it's reasonable to end this review here.