In Greek mythology, Theia "goddess" or "divine" (sometimes written Thea or Thia), also called Euryphaessa "wide-shining," was a Titan.
Theia's mythological role as the mother of the Moon goddess Selene is alluded to in the application of the name to a hypothetical planet which, according to the giant impact hypothesis, collided with the Earth, resulting in the Moon's creation.