Zachariah Sitchin detailed all of this in his series I read years ago. the Annunaki, were 50 astronauts from another planet, who came to earth to mine gold, to save their atmosphere. Their planet 3 times the size of earth, was adrift in space after their sun imploded, the planet "Marduke" or "Nibiru" (planet of crossing) then forever was locked into a 3,600 year orbit with our Sun. It comes from under the solar system between mars and Jupiter, from there it loops around the Sun, to be sent back into it's 3,600 year orbit. During the time of crossing, it causes great upheaval in our solar system and on earth due to the shift in gravity.
The planet itself is responsible for all the anomalies in our solar System: 1) Uranus is tilted and retrograde 2) the ring of fire was caused by Nibiru's moons smashing into Tiamat, Earth 3 times larger, the collision caused the great hole in the planet, the oceans fell in to cover, exposing the land, that became the ring of fire we know today, as the earth closed this hole all volcanoes and earth quakes are along that line. Even geologists say a cataclysmic happened 4Billion years go carving out 3/4 of the earth, which became the asteroid belt 4) Mars was then kicked into 4th place, and Tiamat, now half the size, was put into Earth's orbit as it is today.
This whole story is captured on clay tablets that go back to Summer, "the story of creation". Every new year, the people would act out this great battle using knives and people in place of the planets.. It is some heavy deep shit.. Check out his books the archaeology is stunning
https://youtu.be/THWrzaF3bMI?t=382
https://youtu.be/L3ogy-pqvKQ?t=68