Yes, it was 18 million of years ago that Sanat Kumara came to the Solar System. One of the reasons he took etheric incarnation as the Logos of the Earth was that after the explosion in the Ural Mountains the place had become so dark. However, a call for volunteers had been sent out before he took etheric incarnation to function in the office of Logos of the Earth. The story of the 144,000 volunteers who designed a Plan has its beginning 25 million years ago when the Higher Council of the 250 Star Nations, together with the Elohim of higher dimensions, were assigned to protect and maintain the Galaxy.
As an extension of Elohim, I, Archangel Michael, was assigned to many missions. Sanat Kumara called for volunteers. These actually were one thousand I AM Presences (Monads) who produced 12 extensions of themselves each. Those Higher Selves also projected twelve extensions of themselves each into incarnation. Altogether there were 144 soul extensions for each Monad. They were recorded as the 144,000 in the Book of Revelation. They were joined by others as time went by. In those days the ‘human’ did not exist yet. Other planets such as Venus were inhabited but on higher dimensions.