New discoveries enter consciousness when the moment is ripe.
This is true for both individual unfoldment and for collective experience. The inhabitants of earth viewed the sky as an unchanging family of these seven angels of light. The outermost of these was Saturn whose pale color and stately march through the heavens symbolized the limits of human experience. It was Saturn that was blamed for loss of life, and it was to Saturn that we looked to measure the end of all things. While the telescope was invented in 1608, it took almost two hundred years until the discovery of Uranus smashed the barriers of space and mind.