There do appear to have been some studies on the properties of potential fallback discs formed after neutron star mergers, for example:
Rosswog (2007) "Fallback accretion in the aftermath of a compact binary merger
Cannizzo et al. (2011) "Fall-back Disks in Long and Short Gamma-Ray Bursts
Lyutikov (2013) "The Electromagnetic ...
(I have tracked down the reference that I made in my comment on the question.)
Presumably earth rocks once blasted into space (by volcanism or meteorite impact) gain or lose energy primarily by orbital interactions with planets or moons. Since these interactions will occasionally give enough energy to escape the solar system entirely, presumably anything ...