It's hard to imagine why alien life would be doing this. They'd have to produce a vast amount of this stuff, and then instead of using it for whatever alien-tec

It's hard to imagine why alien life would be doing this. They'd have to produce a vast amount of this stuff, and then instead of using it for whatever alien-tech they've got, they release it to float around in gaseous form. It's not impossible. It's just so bizarre that I'd consider practically any naturalistic explanation to be more likely.