Theia

alternative Thea · alternative Thia

1. Greekhuman sciencesA Titan, the sister-wife of Hyperion.
2. Greekhuman sciencesAn Oceanid nymph (daughter of Oceanus and Tethys), the mother of the Cercopes by Oceanus.
3. astronomyA hypothesised Mars-sized planet of the early solar system thought to have collided with the Earth to produce the Moon.

   1 more example

   According to the reigning hypothesis, about 4.5 billion years ago, shortly after Earth had accreted down into a sphere from its little slub of circumsolar material, another newborn planet, still shaky on its feet, slammed obliquely into Earth with terrifying force. That "giant impactor", named Theia, who in Greek mythology was mother to the goddess of the moon, is thought to have been roughly the size of Mars and to have been pulverized in the encounter, along with a good chunk of the proto-Earth. From that fiery cloud of all-Theia and part-Earth, the scenario goes, our moon soon condensed.

   2014 September 7, Natalie Angier, “The Moon comes around again [print version: Revisiting a moon that still has secrets to reveal: Supermoon revives interest in its violent origins and hidden face, International New York Times, 10 September 2014, p. 8]”, in The New York Times