Colors of airless moons and other places...
- Thread starter Infojunky
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AndrewW
Emperor Mongoose
They can come in all sorts of colours.
Grey/black is generally the only option if the surface is made of rock (e.g. our own moon). You can go from light grey to dark grey too, as seen in the lunar 'seas' vs the lunar highlands. IIRC the photos from the surface had it tinged a little beige too. Asteroids tend to be dark grey/brown.
If they're icy... you can get a lot more variety. Europa is white and brown, Ganymede is dark brown, beige, and white, Callisto is a sort of greenish/brown and white. Amalthea (one of Jupiter's minor moons) is IIRC quite reddish. Io is all sorts of crazy colours (including yellow, white, orange, green, red, and black), but that's because of the sulphur-contaminated volcanoes erupting stuff everywhere (and it doesn't really have an atmosphere to speak of - it's exceedingly thin and somewhat transient). Saturn's moons are mostly white, but Iapetus is literally half white and half greenish-black. Uranus' moons are mostly dark grey/black, and Neptune's moon Triton is white/pink/green.
An icy moon generally wants to be white, but the other colours are caused by contaminants from within (be it salts or dust) or by the action of sunlight on the surface, which changes the chemistry.
Look up pictures of all the moons in the solar system (e.g. here: http://photojournal.jpl.nasa.gov/index.html ) and you'll get an idea of the variety.
Grey/black is generally the only option if the surface is made of rock (e.g. our own moon). You can go from light grey to dark grey too, as seen in the lunar 'seas' vs the lunar highlands. IIRC the photos from the surface had it tinged a little beige too. Asteroids tend to be dark grey/brown.
If they're icy... you can get a lot more variety. Europa is white and brown, Ganymede is dark brown, beige, and white, Callisto is a sort of greenish/brown and white. Amalthea (one of Jupiter's minor moons) is IIRC quite reddish. Io is all sorts of crazy colours (including yellow, white, orange, green, red, and black), but that's because of the sulphur-contaminated volcanoes erupting stuff everywhere (and it doesn't really have an atmosphere to speak of - it's exceedingly thin and somewhat transient). Saturn's moons are mostly white, but Iapetus is literally half white and half greenish-black. Uranus' moons are mostly dark grey/black, and Neptune's moon Triton is white/pink/green.
An icy moon generally wants to be white, but the other colours are caused by contaminants from within (be it salts or dust) or by the action of sunlight on the surface, which changes the chemistry.
Look up pictures of all the moons in the solar system (e.g. here: http://photojournal.jpl.nasa.gov/index.html ) and you'll get an idea of the variety.
Cool, am starting on some terrain and I was pondering what color I could use.
So in general for those Airless rock balls I can use base grays with so other very muted colors. And for the icy moons well I just can have some fun.
The funny thing this topic has come up every so often in one form or another over the years and I have paid only little attention to it. This time when I needed the advice I could get good answers out of the various list and forums archives, so I am finding myself asking it again. Funny how some mems are circular.
So in general for those Airless rock balls I can use base grays with so other very muted colors. And for the icy moons well I just can have some fun.
The funny thing this topic has come up every so often in one form or another over the years and I have paid only little attention to it. This time when I needed the advice I could get good answers out of the various list and forums archives, so I am finding myself asking it again. Funny how some mems are circular.
alex_greene
Guest
A decent knowledge of chemistry would be ideal here. Surface deposits of copper, for instance, could have a distinctive verdigris sheen, while salts of manganese VII yield the violet colour of amethysts and the potassium permanganate they used to use in chemistry lessons in school. Some deserts and varieties of sandstone are russet red because of the huge concentrations of iron ore in them, and so on.
alex_greene said:
Iron oxides are what gives deserts (and Mars) their red colours. But airless worlds won't have things like that - there's nothing to react with. At best they might have hydrated minerals on the surface pushed up from the interior, but even those would be rare. They'd mostly just have normal silicates (most likely basalts and rhyolites) because there's nothing to react with, and the surface would usually be covered by a thick regolith of rock shattered by impacts anyway.
EDG - I understand what you mean about airless worlds not having the color-changing chemical reactions common on worlds with atmosphere.
However, is it theoretically possible to have some sort of "event" that could (dis)color portions of an airless world's surface? Something along the lines of say a large chunk of frozen H20 hitting a world that's mainly iron, and leaving a big red spot? If so, what kinds of things could occur?
I'm not thinking about things you would notice from the 100d limit, but things that might be picked up from an orbital survey. It's one thing to have a relatively featureless grey rock, another thing for the scout ship in orbit to notice a 1 km diameter "splotch" of color on it's surface - that's the kind of thing that as a GM I'd love to throw out to my players:
ME: Roll for your scan.
Player: Ok, I got <x result>
ME: Well, the world is pretty much the featureless chunk of grey iron you expect. There is a small anomoly near the south pole though - a discoloration of the surface.
Player: Really???
However, is it theoretically possible to have some sort of "event" that could (dis)color portions of an airless world's surface? Something along the lines of say a large chunk of frozen H20 hitting a world that's mainly iron, and leaving a big red spot? If so, what kinds of things could occur?
I'm not thinking about things you would notice from the 100d limit, but things that might be picked up from an orbital survey. It's one thing to have a relatively featureless grey rock, another thing for the scout ship in orbit to notice a 1 km diameter "splotch" of color on it's surface - that's the kind of thing that as a GM I'd love to throw out to my players:
ME: Roll for your scan.
Player: Ok, I got <x result>
ME: Well, the world is pretty much the featureless chunk of grey iron you expect. There is a small anomoly near the south pole though - a discoloration of the surface.
Player: Really???
alex_greene
Guest
In the OTU, of course, airless rocks might not have been airless before. Some worlds which are Vacuum planets now may have fallen to some arcane and devastating Ancient weaponry during the Final War, leaving them stripped of whatever bit of atmosphere they once had, and exposing a surface which had once borne life and seen substantial chemical reactions and tectonic processes.
Other mysteries may account for worlds which do not seem to fit the established norms of physics and chemistry, such as the hexagonal storm raging on one of Saturn's poles, and the presence of the unstable element promethium in the spectrum of a star in the Andromeda Galaxy.
All I'm saying is that anomalies can exist, and even seem to have no explanation for them - I should say no currently accepted explanation, because Humaniti hasn't worked out the science of how these anomalies exist yet.
Other mysteries may account for worlds which do not seem to fit the established norms of physics and chemistry, such as the hexagonal storm raging on one of Saturn's poles, and the presence of the unstable element promethium in the spectrum of a star in the Andromeda Galaxy.
All I'm saying is that anomalies can exist, and even seem to have no explanation for them - I should say no currently accepted explanation, because Humaniti hasn't worked out the science of how these anomalies exist yet.
kristof65 said:
Oh all the time. Impacts blow out and expose fresh ice on Ganymede and Callisto to make starkly white craters against the brown background. Iapetus has an entire hemisphere that's covered in black stuff from elsewhere. Mercury has bright craters as a result of pulverised rock. But for rock, it's unlikely that you'd get any variations from grey/brown/black and paler grey/white. Just look at pictures of the Earth's moon and Mercury (especially recent ones from MESSENGER).
Though you won't get a world that is "mainly iron" (at least on the surface) - they'll be rock. Unless something really bizarre is going on - like the world is actually the exposed iron core of a formerly larger planet that got so blown apart than none of the rest of it is left (which is most likely impossible).
alex_greene said:
Well, strip the Earth of all life, water, and atmosphere and I'm sure you'll see some colour variations - at the very least you'll have dark ocean basins and lighter continental plates, and all sorts of intricate fold patterns that were exposed by erosion that isn't ongoing anymore. But over the aeons the colours will fade as the surface gets slowly buried under the debris of more and more impacts.
All of which probably have a perfectly rational explanation (the storm is just down to convection cells. Straight edges and geometric patterns are quite possible in nature after all). As for the star, I've not heard of that one, but supernovas can theoretically generate transuranic elements - maybe the star got 'seeded' by the debris from a nearby supernova and the promethium hasn't decayed yet. Or some very weird nuclear process is going on inside them (looking it up now, apparently only two stars are currently known to have such weird elements). Unusual anomalies, sure, but perfectly natural - physics and chemistry can still throw oddballs at us iwthout having to rewrite everything we know about anything, and tbh I don't think any planets (airless or otherwise) will really be the same as any other - they'll all have their own odd quirks that make them unique.
alex_greene
Guest
That's been verified, then? Classic.
HR465 in Andromeda is one. http://periodic.lanl.gov/elements/61.html
Absolutely. It's working out how an anomaly could be formed through the natural processes of planetology, physics and chemistry that makes worldbuilding such a joy.
Thanks. I thought it wouldn't be out of the ordinary, thanks for the examples, too.
I could be wrong though.
Yeah, I know. But iron and the color of rust were more beleivable than the other reaction I had in my surface thoughts - copper, and it's green corrosion. I figured a chunk of solid iron floating around out there was more beleivable than a chunk of solid copper.EDG said:
I could be wrong though.
