"The Dark Star website explores the existence of an additional, massive planet in our solar system. It is usually referred to as Planet X. Recently, astronomers and astrophysicists have begun to name this putative object 'Planet Nine'. Other ideas about Planet X focus upon references made in various mythical writings to rogue gods and fabled worlds"
https://darkstar1.co.uk/
The Great Year
"Just as the Earth’s spin on its axis causes day and night and its annual orbit around the Sun is responsible for the ongoing cycle of the seasons, what if there is some greater celestial cycle, lasting thousands of years, slowly influencing the rise and fall of civilization across the globe?
To many ancient cultures, the answers lie in the stars. In their view, time moved in a cyclical pattern, with human civilization and consciousness rising and falling as great ages came and went. Vedic scholars spoke of the Yuga Cycle, a great circular progression of ages; and Plato taught of a large cycle of time that would slowly return us to a "Golden Age". He called this cycle: The Great Year.
The Great Year investigates commonalities in these beliefs and looks back into time seeking answers to questions that still loom over science today. How far back do humankind’s roots really go? What did the ancients know about the stars and their movements and what can we learn from them? How was the Precession of the Equinox, the slow progression of the stars across the sky over thousands of years, used to mark the rise and fall of these great ages by the ancients? Many cultures spoke of an unseen sun driving Precession and causing the cycle of this Great Year. Could there be an unseen companion to our Sun? The Great Year examines this theory and finds that perhaps these ancients were really onto something!"
"The great year is a period of 24,000 years"
https://thegreatyear.com/facts/