Theia

Proper noun

Theia

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