planetagai is incorrectly written and should be written as "planet gaea" being its meaning:
The planet Earth, in Greek ge ges and Greek mythology Gea, Gaia or Gaya, born of the primeval chaos, the Mother Goddess, mother and wife of Uranus ( 41 heaven; whose union were the Titans, Cyclops and Hekatonkheires, ancestors of the Greek gods. Some consider the planet Gaia as a great living being it is adjusted as a system in equilibrium, in an attempt to rationalize the classical myths.
