Tightly Packed Planets Spotted Around Sun-Like Star | Wired Science | Wired.com: "The Kepler space telescope has spotted the most tightly packed exoplanet system yet, with five planets orbiting around the star KOI-500 within a fraction of the distance between Mercury and our Sun.
The system was discovered by Darin Ragozzine, a planetary scientist at the University of Florida at Gainesville, and his team. It’s roughly 1,100 light-years from us, in the direction of the constellation Lyre. Its five planets are each slightly larger than the Earth, but their orbits are remarkably close to KOI-500 — 150 times smaller than the orbit of the Earth. That’s even less than the orbital distance of Mercury. Yet despite flying around so fast that it’s only a manner of Earth days for each “year,” they exist in an orbital resonance that keeps them from crashing into each other or falling into the star."