Mother Earth vs Rhea

Mother Earth

name

  • The goddess of the earth in various cultures. 

  • The personification of the Earth, (chiefly) conceived as a fertile, nurturing, and loving mother. 

Rhea

name

  • A female given name from Ancient Greek in occasional use. 

  • A Titan, the daughter of Uranus and Gaia, the mother of Demeter, Hades, Hera, Hestia, Poseidon, and Zeus. 

  • The asteroid 577 Rhea. 

  • Saturn V, one of the moons of Saturn. 

  • A surname 

How often have the words Mother Earth and Rhea occurred in a corpus of books? (source: Google Ngram Viewer )