  The field of exoplanetary science has experienced a recent surge of new
systems that is largely due to the precision photometry provided by the Kepler
mission. The latest discoveries have included compact planetary systems in
which the orbits of the planets all lie relatively close to the host star,
which presents interesting challenges in terms of formation and dynamical
evolution. The compact exoplanetary systems are analogous to the moons orbiting
the giant planets in our Solar System, in terms of their relative sizes and
semi-major axes. We present a study that quantifies the scaled sizes and
separations of the Solar System moons with respect to their hosts. We perform a
similar study for a large sample of confirmed Kepler planets in multi-planet
systems. We show that a comparison between the two samples leads to a similar
correlation between their scaled sizes and separation distributions. The
different gradients of the correlations may be indicative of differences in the
formation and/or long-term dynamics of moon and planetary systems.
