oscillation

So as a full member of both the American Astronomical Society and the American Physical Society, I get sent issues of the magazine Physics Today. Well, I was going through the April issue, when I saw this article: Cosmic Sound Waves Rule by Daniel J. Eisenstein and Charles L. Bennett That first name sounds familiar. Why? Because he's my boss! The article requires a subscription, but seeing as how this is what my research is, why don't I tell you what the big idea is. The Universe is full of dark matter, normal matter, and radiation. When it's young, the radiation is more important than matter…