Complex sentence: Scientists are not yet sure why the planet orbits opposite to the star's rotation; theories include a collision with another planet or the intervention of a smaller planet-like body working to change WASP's orbit by tilting it via the Kozai mechanism.
Split into simpler sentences: Scientists are not yet sure why the planet orbits opposite to the star's rotation. Theories include a collision with another planet or the intervention of a smaller planet-like body working to change WASP's orbit by tilting it via the Kozai mechanism.