Feivel: There is no need for the snark. The Rambam himself says that he quotes Aristotle. This part of the nature of the stars is a basis of Aristotelean metaphysics. It’s not a stretch to think he’s quoting Aristotle here. It’s the simplest explanation for this concept.
Now, the Rambam did not quote those things from Aristotle that he knew went against his tradition. The Rambam was certainly not an atheist, after all. However, he did think that Aristotle got most things right, include almost all of his theories on physics and metaphysics. So when the Rambam quotes an idea that is a direct Aristotelean idea, why not assume it comes from Aristotle? Yes, he thought it doesn’t go against the Torah, and that matters a lot. But it doesn’t mean that Aristotle isn’t the Makor (of course, Aristotle being the Makor in no way makes it wrong, either). And it also explains why the concept wasn’t quoted by other Rishonim. The Rishonim, in very large part, kinda just ignore the ideas in the Rambam that came from Artistotle.