THEIA collision with EARTH

[Michael Grove]

 The name of the hypothesised protoplanet is derived from the mythical 

 Greek titan Theia /ˈθiːə/, who gave birth to the MOON goddess Selene.

Giant impact hypothesis 
from Wikipedia, the free encyclopedia 

This designation was proposed initially by the English geochemist 

Alex N. Halliday in 2000 and has become accepted in the scientific

community.^[2][11] According to modern theories of planet formation,

Theia was part of a population of Mars-sized bodies that existed in the

Solar System 4.5 billion years ago. Indeed, one of the attractive features

of the giant impact hypothesis is that the formation of the Moon fits into

the context of the formation of the Earth: during the course of its

formation, the Earth is thought to have experienced dozens of collisions

with such planet-sized bodies. The Moon-forming collision would have

been only one such "giant impact" and, perhaps, the last.

.