You know what bothers me about all world cosmologies?  The positive and negative energy planes aren't defined at all, just as shells or locations with completely vague senses of scope and distance.  They aren't "things", but they are still incredibly important and undervalued in all cosmologies.  (Forgotten Realms even destroyed them by mixing them into the elemental chaos!)  I want to make the positive and negative energy planes what they have always been but never seen as- the most fundamental and influential forces in any and all multiverses- pure creation and pure destruction.  A White Hole, and a Black Hole.  Singularities and the cosmic oblivion that surrounds them.

This also gives all gods a singular purpose, self preservation.  Positive and Negative are not good or evil, they are a choice.  Continue existing, or fall and never be heard from again.  Even the most evil or chaotic creatures still wish to live, and so all gods on all planes could agree on one thing. 
Don't look down.

  I went in for Jury Duty on Monday, and had to pass the time sitting and waiting somehow.  I looked up at the lighting fixtures on the ceiling, and they captured my imagination.  eight seven foot diameter chandeliers of brass tubing, simple, not impressive, but just complex enough.  Descending from the ceiling of the room was a brass tube that grew into a mess of twelve lights, eight lower cylindrical lights and four elevated hourglass shaped lights.  At the center of it all, the center tube continued down and ended in a perfectly spherical brass ball, glimmering with the reflections of all of the other lights, showing bands of white gold and brass as I shifted my head.  It hit me after a few minutes, that this was similar to the Orrery model of Dungeons and Dragons cosmology, with a planet and the planes all moving about in space like a solar system.  But this was fixed, with a series of pipes connecting everything to a center pillar, holding it up from the force of gravity.  After much speculation, I came up with a cosmology that I just have to share with you all.  I hope you find it fascinating and useful for a new way to view or reinvent the planes in your homebrew!  I present, THE CHANDELIER WORLD COSMOLOGY!  Also known as the Black-Hole/White-Hole cosmology.

This cosmology really came together after I asked myself "What is the center tube connecting to?  The Matrix?  The multiverse?  The Outlands?  An Overgod?  A power source?  A power source.  Imagine a new creation story focused on just two objects, a paired White/Black Hole system.  A black hole as you know is an all consuming death machine consisting of a singularity and the madness that surrounds it.  A White Hole is what is theoretically on the other end of a Black Hole, a singularity spewing out energy into the world around it.  I imagine everything in a world cosmology coming from the Positive Energy that is spewed out by the White Hole and what happens to it as it spirals down towards complete destruction.  All consuming primordials, otherworldly outlanders, and the first titanesque gods could appear in this mess of creation and destruction.  The trails of energy would coalesce into knots, strands, bumps, bulges, the first beings/planes created by the life of a never-ending stream of pure Positive Energy, constantly swimming upstream to avoid the doom below. 

And that is what drives the beings of this world, finding a way to exist suspended between death and life.  The first magic of the world is a power of "Antigravity" that can go against the pull of the Negative Energy Singularity.  As forces clash, titan gods create a disk at the edge of the white hole, able to just barely survive the blinding light of the Positive Energy Singularity, and live selfishly and think.  These Titans are the gods of pure alignment, Neutrality does not exist yet.  These are the first Evil, Good, Lawful, and Chaotic entities, who would go on to create their respective planes.  The primordials below them are too suffused with Negative Energy to attain this position.  With "antigravity" magic, they can ponder what other powers this energy source provides.  They conceive of the concept of Cooperation, and immediately regret their decision.  The Gods are born from the titans, "Impure", CG LG CE LE.  The mixing of alignments allows cooperation, deception, alliances, and organized conflict.  The Gods immediately descend upon eachother, and clash and combine and come undone and come together over and over, each time sinking further from the Disk that would become this world's version of Sigil.  The Gods come into contact with the Primordials down here, and fight an epic war, completely unaware of the Black Hole beneath them, having been born and lived so close to Positive Energy.  The last action of the old Titans is to remind their children of a notion they know not, death and the end, and give them "antigravity" and pressure them to not be distracted by their wars.  This creates Neutrality, and the Pure Titans become NE, LN, CN, and NG, retreating from the politics to focus only on staying alive.  This is the power balance, the Titans are stronger but cannot cooperate. 

Now fearing their own deaths, and having destroyed the primordials, the gods descend upon one another, fighting for access to the streams of Positive Energy they all claim, like dying animals to an oasis.  Unlike the Titans, they cannot help themselves from interfering with one another's streams, due to their beliefs.  Good worries about evil hoarding it for themselves, law worries about theft, distrust builds.  This begins the greatest work the gods will ever produce, a lottery.  The Material Plane, a plane where the stream of Positive Energy can be divided among the gods according to their worthiness.  LG had the idea of the mortals to decide for them.  CG demanded a chance system, giving way to free will.  CE, likely tainted by Negative Energy, made the mortals mortal- introducing death tot heir lives, so that the positive energy would be up for grabs upon a mortal's death.  LE worried about not getting their fair share, and put forward the idea of souls coming from dead mortals to their favorite planes.  A new god of True Neutrality was made patron of the mortals' world, and the Nature God demanded the others not interfere too much with the lives of mortals, or Nature would take the world for its own.  The PMaterial Plane itself was held in suspension with a sun and a 'prime tube' that life would flow from and back into, to be given to the planes.  If the gods failed to uphold their end of the deal, the PMaterial Plane would sink deeper towards destruction, almost like it was on a piston. 

The first Rogue Planes appear, as somehow, four Primordials bring their planes to destroy the Gods and continue the war, throwing themselves at the PM, introducing the elements.  This sends the PM cascading towards oblivion, the Negative Energy drawing so near as to form the Shadowfel and introduce the Mortals to the darkest ideas of the universe.  In a second Primordial War, the gods seal each Primordial into the planes they created, trapping them in the Elemental Planes.  The god of Nature splits themselves into four parts to secure each of these deadly tombs on each plane, leaving nature as a separate force from the mortals.  What was once an eternal eden of philosophical decisions and discovery was now a world where the mortals must find their own ways to survive, and they had just almost all died. 

The mortals invent their own gods, impure of impure, mixed of mixed, complicating the cosmos with the Planes of Conflict.  They set one another at war over resources, the Gods see a mirror, as the mortals fight over sources of survival just as they had.  As the first kingdoms arise, gods of war, trickery, tempest, etc are created and fill the cosmos with new younger weaker gods, creating eight new "lower" planes, fundamentally closer to the Negative Energy Plane.  The Shadowfel and Feywild complete, the cosmos become organized, and the Transitional Planes (the tubes connecting the various planes) and all their facets are fully formed.  The last thing to happen is something I have always seen as the pinnacle of Worldbuilding- a calendar.  16 months for 16 planes to serve their duty to lift the Prime Material plane up with "antigravity", by "shining their light" on the central spinning sphere, stars in the sky, constellations, auroras.  The eight shortest months are for the weakest planes, four moderate months, and four long months for the planes of the Titans to pull the weight of their distracted descendants.  At the end of each month, a New Moon to show that the world is at its weakest, and has sunk the lowest down.  The Full Moon is the fully charged part of the month, and Gods are rewarded with Holy Days for their support of the "Great Lottery". 

From here on it's all good to be modified!  Want Kelemvor to have a city of the dead "waiting area" for the souls to be distributed?  Put it in the bulge of the central rod.  Want a distinct astral and ethereal plane?  Have one be the main tubes and another being the light streams, or chains, or an arterial system of veins and capillaries and muscles.  Want the River Styx?  You can have a plane weaving up and down the weaker and stronger evil planes as a thing created as an alliance between all evil planes to have an advantage against good.  Want Sigil and the traditional outlands?  I would say put them as high up as possible, or have a kind of "rainbow space road" that floats like a disk or set of saturn-rings above all the planes.  The Elemental planes need to be more than just floating balls  that orbit the material?  Sure, have a swirling accretion disk around the PM that serves as the elemental.  Want a boundary to really seal off the PM from the Outer and Inner Planes?  Have the Ethereal be a bubble of galactic nonsense that shields the PM from the elemental chaos or planes that shine too brightly, or that makes the night sky seem so beautiful and vague. 

What do you think?  Is it interesting to have the planes not all be on equal footing?  What do you think about the Positive and Negative Energy planes in other cosmologies?  Do you like the Astral as a "Network of tubes"?  I would love to hear it!  Working on putting all thee mess with the calendar together right now.  I've got eight 21 day months, four 24 day months, and four 25 day months, with one extra day for something special if I think of it.  Maybe a "day of the elements" that completes a cycle each year, changing each year from fire to water to air to earth, and then having a leap day on the final year to get the full 365.25 day year.    -Patt

This is quite an interesting concept. I'd not use it for the FR specifically, but if I didn't already have a cosmology for my homebrew world, I'd love to use this.

(Sidenote, you typed 265.25, rather than 365.25 - I assume that was unintentional?)

Thanks for the edit note and the compliment!  I would love to hear some thoughts on failings or missed opportunities in the methodology.  One thing someone in the court room told me was that some of the lights in the room were shining up too, so there could be a far realm of coalesced positive energy "above" the white hole too, just for more shenanigans.