"And I shouldn't wonder, if you will excuse my interrupting you," said Zaidie, "if the moons themselves have been made up of a lot of these things going together when they were only gas, or nebula or something of that sort. In fact, when Saturn was a good deal younger than he is now, he may have had a lot more rings and no moons, and now these aerolites, or whatever they are, can't come together and make moons, because they've got too solid."
I'm wondering if it was generally accepted in the 1930s when Weinbaum was writing his planetary stories.