Although there have been intervals of colder and warmer weather..........the general trend is a cooling off, and a puffing out effect.........since 4.6 billion years ago.........

Date	Event
4600 Ma	The planet Earth forms from the accretion disc revolving around the young Sun; complex organic molecules necessary for life may have formed in the protoplanetary disk of dust grains surrounding theSun before the formation of the Earth.[4]
4500 Ma	According to the giant impact hypothesis the Moon is formed when the planet Earth and the planet Theia collide, sending a very large number of moonlets into orbit around the young Earth which eventually coalesce to form the Moon.[5] The gravitational pull of the new Moon stabilises the Earth's fluctuating axis of rotation and sets up the conditions in which life formed.[6]