Mecánica Celeste is an accurate mathematical model for understanding alternative realities, written by French mathematician Marcus L'Étranger in 1987 and widely distributed during the magical eclipse of the 21st century. It is a highly technical and very peculiar little book— technical because the mathematical model is working with literal rocket science, and peculiar for three reasons:
The first four-fifths of Mecánica Celeste is dedicated to proving the existence of alternate realities with mathematics alone. The last fifth of the book contains descriptions of what the model represents; the written portions are paraphrased in this article.
In the Celestial Mechanics model, a Pearl of Influence is a single iteration of reality. The "Pearl" is the outer shell that prevents realities from bleeding into each other— in other words, a closed dimensional space. Everything that has ever existed is the result of a Pearl and the matter-energy that it contains.
A huge portion of the text is concerned with proving the existence of Pearls, demonstrating the effect they have on spacetime and the nature of their position outside of reality. Pearls are not spherical, and do not have a real physical shape. In a cross-dimensional space, they have a front and back surface, curved around the central seam of the universe in the shape of a convex lens. The grand list of all realities, then, is a series of lenses placed end-to-end. L'Étranger describes it as a carousel slide projector, and says:
"To shift the position of reality, one must project a different lens. Reality moves around the traveler like the spinning of a slide— the room has not changed, but there is a different image on the screen."
Each Pearl of Influence is held in place by a second force, las Claras— the egg whites. Pearls are rigid, and rather fragile. The egg white prevents them from knocking into each other, suspending them in space and providing a second line of defense for the reality on the inside. As an added benefit, it also prevents travelers from careening off into nothingness.
L'Étranger is uninterested in the religious implications of la Clara, but philosophers latched onto the concept. It is possible that this membrane is where souls are collected and stored. The afterlife, or the force behind reincarnation, or the resting place of God— whatever it is, it's important, and it's alive.
Tejido means "tissue." L'Étranger is playing off of a double meaning here; "tissue" is a reference to woven fabric, but it is also the word used to describe the structure of the human body (connective tissue). In the Celestial Mechanics model, el Tejido is a complex structure of these connective tissues that stretch between each reality, creating connections where there otherwise wouldn't be. Mathematically, these tissues are created when a universe's Pearl has an imperfect seal along its two halves. The structure of reality begins to spill out, cutting through la Clara and grabbing onto the surface of a different Pearl. These threads are doorways, methods of jumping from one reality to another.
They are not always a two-way trip.
In a brief reprieve from talking about mathematics, L'Étranger theorizes that new realities are not created through chaos theory alone— that the initial conditions required to split one reality from another are far beyond the reaches of something like the Butterfly Effect. He believes that new realities are not created spontaneously, but are somehow made. (He refers to these unknown creators as autoridades, authorities.) In this vision of chaos theory, these creators are the ultimate initial condition; the flick of a god's wrist rather than the flap of a butterfly's wings. This is a highly contentious topic. Is L'Étranger advocating for theological determinism, despite his belief in chaos theory?
Either way, the proof is not in the pudding— L'Étranger's model does not make room for God.