 You come up with suspended particulates. You come up with light. And this goes to Mallet's research. You come up with light, but it's got to be at a very particular angle. And then there's the matter of the Foo Fighters in World War II. That's right, those little disks, whatever they might have been. And it turns out that there's a pretty good case to be made that those were caused by sonoluminescence.