 You can show how hard it is to detect a planet transiting a star. Just back away about 50 feet from your audience and orbit the planet around the star. This can be done day or night. Ask your visitors if they can see when the planet passes between them and the star. They're not likely to be able to. The Kepler mission will be detecting transiting planets around stars hundreds to thousands of light years away. So how do you suppose Kepler will do that? Let's find out. You'll want to do this in a darkened room or at night and plan to have a helper. Fold the white card in half like this. This card represents one of the detectors aboard the Kepler spacecraft. The light from this model star is being detected here in how brightly lit the card appears to us. We're going to make different sized model planets orbit around the model star like this. Since the Kepler detector cannot see the planet directly, we must block the planets and only look at the detector. Kepler will look for stars that dim, then brighten, then dim again as the planets orbit them. Kepler will only detect the dimming of a star. It will not see the planet itself. Here's a large planet. Watch the card as we make the planet orbit the star. Can you see the light dim as the planet goes between the star and the Kepler detector? Let's try a mid-sized planet. Okay? Do you see the light dim now? Well, we're especially looking for Earth-sized planets. Think this one is going to be harder to detect? It may be really hard to see. Actually, all these beads are scaled way too big as planets for this star. Being able to detect the dimming of a star by an Earth-sized planet is sort of like being able to detect the dimming of a giant search light by a ladybug walking across it. Essentially, that's what Kepler will do. Detect that very, very small dip in light from the star. You can find more tips and presentation suggestions in the manual.