LD: With a light curve, we have a curve showing brightness with time. The first thing we did with Kepler-16 is we noted that some of the dips were regular, some were shallow, and some were deep, so there must be a bright star and a faint star. We thought, maybe there's an eclipsing double star in the background that happened to get in the same measurement, because Kepler has big pixels. If it was a background eclipsing binary, the curve will be deep, shallow, deep, shallow. But then the binaries switched places. It was a deep dip, shallow dip, shallow dip, deep dip. It was like, "Whoa." How could it suddenly switch directions and go the other way? That didn't make sense. But what did make sense was this was a circumbinary object. It goes across the big star, and then the little star, and all the way around them both. When it came back, it just happened that the little star was in front; it changed places.