  Over time, the rotation throws lighter ingredients towards the edges of the whirl and pushes the heavier ones to the center (B15), thus putting more dark and heavy ingredients like earth in the center and throwing air and aether (fire) away from the center. This gives the traditional Greek picture of our Earth (itself a mixture of all ingredients, with earth and heavy ores and minerals predominating) covered (in many places) by water, with air and the fiery reaches of the heavens.