if you paid attention to the beginning of the game, the Traveler made planets such as Mars and Mercury (specifically making Mercury a "Garden World") habitable, including the moon. If Mercury became a Garden World, and if humans were able to build civilizations on planets that would most likely kill them before the Traveler was ever discovered, than that means the Traveler was capable of creating an atmosphere that could sustain life, thus the atmosphere on the moon results in the twinkling stars. also there are no visible bodies of water on [u]the surface of the moon[/u] so likely there is no water to evaporate and form clouds. The Traveler also may, or did, create some possible form of gravity for the planets. I'm surprised you didn't argue about any gravity differences on Venus (though Venus does have gravity similar to Earth) or Mars, or the fact that Venus has trees and plants on it... and water/rain, like why isn't it deadly hot anymore? where did all the sulfuric acid clouds go? we may never know.