Four planets locked in a perfect rhythm around a nearby star (HR 8799) are destined to be pin-balled around their Solar System when their Sun eventually dies, according to a study led by the University of Warwick that peers into its future. Astronomers have modelled how the change in gravitational forces in the system as a result of the star becoming a white dwarf will cause its planets to fly loose from their orbits and bounce off each other's gravity, like balls bouncing off a bumper in a game of pinball.