What conceptual shift resulted from concluding the Moon was imperfect and Earth-like?

Answer

The Earth was demoted from its unique, central position to merely one planet among many imperfect worlds.

The realization that the Moon was imperfect dissolved the fundamental barrier separating the corruptible terrestrial realm from the eternal celestial realm, paving the way for viewing Earth as just one planet in a system.

What conceptual shift resulted from concluding the Moon was imperfect and Earth-like?
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