  The most significant periodicities in the terrestrial impact crater record
are due to the human-signal: the bias of assigning integer values for the
crater ages. This bias seems to have eluded the proponents and opponents of
real periodicity in the occurrence of these events, as well as the theorists
searching for an extraterrestrial explanation for such periodicity. The
human-signal should be seriously considered by scientists in astronomy, geology
and paleontology when searching for a connection between terrestrial major
comet or asteroid impacts and mass extinctions of species.
