Neighboring exoplanets appear to come in similar sizes. But is this a result of observational bias?
The key to understanding how these worlds are built is to consider where they are missing.
Planets are occasionally found swallowed by their dying host stars. Where and how often does this happen?
Radiation from massive stars can melt away protoplanetary disks. What can the leftover disks tell us about the environment from which they formed?
What can highly inclined giant worlds tell us about the presence of terrestrial companions?