Since Gurdjieff has choosen to present his ideas in part in the form of allegory, one can read those parts of this book simply as fascinating science-fiction.
The story opens aboard the space ship Karnak. Beelzebub is traveling to a conference where his sage advice is needed on matters of cosmic significance. He is accompanied by his grandson, Hassein, and his old and faithful servant Ahoon.
As they travel, Beelzebub regales Hassein with tales about the Earth, about events in the universe, and about cosmological and psychological law. Beelzebub tells Hassein how he happened to become interested in the planet Earth.
During his youth, he intervened in affairs that were of no concern to him and as punishment was banished to Mars, in a “remote corner of the Universe” (our solar system).
Gurdjieff made it quite clear in "Beelzebub's tales to his grandson" that man no longer has to serve the moon. The original reason that the organ Kundabuffer was implanted in man was because that at that time in the solar system's history, the consciousness of men was forced, due to unforeseen circumstances in the form of outright mistakes on the part of higher cosmic individuals, to feed the earth's unintended and accidental satellite.
To put it quite bluntly... according to Gurdjieff, mankind got screwed.
Guernica by Pablo Picasso,
From: Zero Point
“... it was possible sometimes to observe very strange manifestations of theirs, that is, from time to time they did something which was never done by three-brained beings on other planets, namely, they would suddenly, without rhyme or reason, begin destroying one another’s existence. ... from this horrible process of theirs their numbers rapidly diminished ... .” (p. 91)
“I must tell you that the chief particularity of the psyche of your favorites, namely, the ‘periodic-need-to-destroy-the-existence-of-others-like-oneself,’ interested me more and more with every succeeding century of theirs, and side by side with it the irresistible desire increased in me to find out the exact causes of a particularity so phenomenal for three-brained beings.” (p. 318)
From Google books – by David Applebaum
The question of time was first felt by humans not as an abstraction but practically, in the rise and fall of rivers, the periodic return of the moon and constellations of stars,the migration of prey, and the progression of seasons. At the dawn of civilization early sciences — geometry, astronomy, and music — arose and were specific solutions to the question of time.
Consciousness did not yet distinguish the inner from the outer, or experience from the cosmos to which it belonged. Recurrence was manifest also in human life, in the ebb and flow of opportunities, moods, and sensations. But if purpose was to survive outer change (like the boundaries of farmers' fields in spring floods), humans were called to discover a relatively stable presence, an awareness conscious of impermanence. Thought in this regard followed one of two paths. One led to the question of appropriate action: how to respond to a moment's unique demands without losing sight of the background sameness of the cycle. Hunting rituals were early solutions. They were followed by agrarian festivals and later, oracular texts such as the I Ching and the Tai Hsuan Ching.