Timescales relating to human development and the terrestrial environment
*Very approximate. The slowness of human development during the ice age contrasts noticeably with the speed of cultural evolution following its end. There is much overlap of astronomical and cultural timescales, and indeed the zodiacal cloud and Taurid meteors are visible even now, while Enckes comet is just below naked-eye visibility. In antiquity with the complex of debris much more active, it is likely that the prime comet, lesser comets, and debris were regularly visible in the zodiac, and associated with fierce annual fireball showers and occasional impacts.
In seeking evidence of the ancient turbulent sky, we should not necessarily expect descriptions, perhaps four or five thousand years old, to be given in modern scientific terms. We do not seek comets tracking along the zodiac but gods wandering along a celestial river; rather than evanescent patches of light we should seek temporary celestial islands; rather than fireball swarms and a Tuguska impact we expect celestial thunderbolts hurled in anger; and in tales of the worlds end, we should be alert for indications that celestial catastrophe came specifically out of the constellation Taurus the Bull, or in more remote epochs, because of the evolution of the meteor orbits, out of the neighbouring constellation Aries the Ram.
Fred Hoyle and Chandra Wickramasinghe