Suppose we have an Earthlike planet, with a rocky moon orbiting it. Under what conditions would dark lunar maria form on its surface, and would they always be on the side facing the planet? For Earth’s Moon, it appears that the maria face the Earth due to heat radiating from the molten Earth. How universal is this phenomenon? Does it depend on, for example:
Whether the moon was formed in an impact, or if it was captured?
The size of the moon, from the smallest rocky body that forms a sphere under its own gravity, to being the equal to the size of the planet (a double planet)?
The presence of gas giants in the solar system? (It seems Earth’s Moon got its maria from asteroid bombardments caused by Jupiter and Saturn.)