Planetary Formation

A new study using data from NASA's Kepler planet-hunting probe has found a solar system put together much like our own.

Three huge exoplanets orbit a sunlike star, all in the star's equatorial plane-- just as the eight major planets in our system orbit the Sun.  Scientists take that as evidence in favor of the standard planetary formation theory, which holds that planets form in disks of gas and dust that orbit in the equatorial plane of a star.  Later gravitational interactions among planets can change orbital inclinations, but this young system supports the notion that planets begin in the same plane.