How would I make a moon appear black in a night sky that has a nebula visible in it?

So, I'm developing a world for my fantasy setting, but I thought it'd be neat if this particular world had a nebula visible in its night sky. (So, it might not be a nebula like the kind we have in the real universe.) Anyway, I thought maybe there might be a point during the year where the moon would be completely black but it would still be visible because the nebula would be located behind it. Problem is, I can't figure out how to make that happen, except perhaps during a lunar eclipse. But the moon isn't black during a lunar eclipse, it's red. So, how would I be able to get this black moon with the nebula as a backdrop to happen?

Update: So, I've received a lot of great feedback, but I should probably clarify something about the nebula for people so we're all on the same page. It isn't a nebula in a literal sense. This is a fantasy setting, after all. The nebula was created when one god sucker-punched another god during The Divine War, a period where a whole bunch of gods were fighting with each other. Most of their fighting was on another plane of reality, but sometimes the fallout carried over into other universes.

The nebula, which the Orcs refer to as "The Sky Wound," isn't composed of the same materials as nebulae are in the real universe. It's a massive cloud of divine energies that bled over from the plane where the gods were fighting. The god who got sucker-punched lost pieces of himself, which were scattered across the mulitverse. One piece might be at the center of the nebula, but I'm not sure of that. (It seems a bit obvious.) Anyway, the nebula is generating light, not reflecting it. As the god has been waking up from being KO'ed for thousands of years, the nebula has shifted from crimson to green. Currently, because he's fully awakened, it's completely green. As he locates the pieces of his being that were broken off of him, the nebula will shrink and ultimately vanish.

Regarding the moon, it's probably around the same size as ours. I don't want it to be so close that it will be causing all kinds of tidal and other issues for the Orcs, so it can't be in a position where the red wavelengths filtered through the planet's atmosphere will be unable to reach it during a lunar eclipse. That leaves us with finding a way to negate the red wavelengths from being reflected back to the planet during an eclipse.

The moon having an atmosphere is the most appealing explanation for me, since it presents some interesting opportunities. As I said in one of my comments, portals between planets are a common thing in this setting. I've been considering the idea of some worlds having portals that connect to their moons for a while now. It'd be fun if the Orcs could go to their moon to gather certain resources. Mind you, this doesn't mean the atmosphere would be breathable. In fact, I'd prefer that it not be. All it should do is give them enough protection from the sun and the vacuum of space that they don't have to worry about those issues. Beyond those two things, however, the atmosphere should be of no benefit. The Orcs would need to come up with some kind of magical life support system to protect themselves from it enough that they could mine for resources.

So, how do you guys think we could pull something like that off? Just to recap, the moon will have an atmosphere that does not reflect red light and will prevent the Orcs from decompressing, freezing, or burning to death when they use a portal to reach the moon. There also needs to be something keeping them safe from the lethal radiation coming from the sun. Magic can be a solution to these problems, of course, but I'm looking for non-magical explanations since I don't want to be using magic as a crutch. In other words, I'd prefer that the only solution magic offers to setting up mining operations on the moon is in the form of the Orcs having a life support system providing them with breathable air.

This is getting fun.

posted over 5 years ago

Patrick-Leigh‭

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