The MIRI can trace the evolution of planetary systems from their formation to mature systems identified through their leftover debris. (animation from C. J. Hamilton)

For example, the following image shows the Spitzer/MIPS image of the debris disk around Fomalhaut, as released in the initial Spitzer press conference (left), and how the system might look to MIRI (right).

The MIRI image reveals the assymetries maintained by gravitational resonances with a giant planet, and hypothesizes an inner disk clearing maintained by another planet (both planets are detected).

The MIRI will also be able to probe the nature of giant planets around nearby stars, and the minerals in their debris systems, both through spectroscopy.