The evidence for a major population of
small comets (SCs) is summarized in two steps.
First, we briefly summarize our previous work.
Second, we describe recent work that continues to
find SCs. When new capabilities become available
that can detect SCs, we expect to find them and
this is occurring. At present, their detection is
a haphazard process and we advocate a dedicated,
optimized search program.
We define SCs as those icy bodies (i.e.,
sublimating bodies) with radius less than 1000
meters. Often the existence of SCs is inferred
from effects ascribed to them. These “effects”
include: lunar cratering; cratering on Ganymede;
excess interplanetary hydrogen; delivery of
volatile materials to the terrestrial planets; and
a source of fragile bodies entering the Earth’s
atmosphere. While some of these indirect methods
support the existence of SCs, direct observations
are clearly preferred.
Water and the Interior Structure of Terrestrial Planets and Icy Bodies