Planet Orbiting Two Stars Found

NASA's Kepler planet hunting spacecraft has made a particulary interesting discovery-- a Saturn-sized world that orbits two stars, not just one.

Such worlds have been popular among science fiction writers for decades, but this is the first example of the arrangement found in nature. Now that one has been found, astronomers expect to find others.

The next step will be working out how planets form in such orbits. Current planetary formation theory works well enough with one star, but adding another star, and therefore another powerful gravitational influence and a competing solar wind, would seem to complicate the process. In the case discovered by Kepler, both stars involved are smaller than the Sun. The relatively low energy in this specific developing system might be a factor in explaining the planet's current orbit.