What revolutionary concept did Galileo promote by stating the Moon was *like* the Earth?

Answer

Cosmography—that different celestial bodies might share common physical characteristics.

Stating the Moon was like Earth was a profound step toward cosmography, suggesting celestial bodies shared familiar physical characteristics, blurring the metaphysical line between Earth and the heavens.

What revolutionary concept did Galileo promote by stating the Moon was *like* the Earth?
discoveryGalileoastronomytelescopeMoon