Fiction:Elysium Cold War/Temporal Mechanics

Chronography

Chronography is the study of how a given event or entity's presence is distributed throughout time; the temporal equivalent of geogrpahy

Spissitude of Free Travel

Due to general relativity, forward time travel is technologically much easier to accomplish than backwards time travel, requiring only relativistic velocities or proximity to black holes to accomplish. In contrast, backwards time travel requires constructs like wormholes, closed timelike curves, or Chronoscopic Essence. Together, these are collectively referred to as antisagittarian time travel. This puts a limit on the range of backwards time travel before the energetic/technological requirements are too great.

This creates a region of the timeline called an entity's Spissitude of Free Travel (SoFT). Here, the back-in-time, or kata boundary is defined by the distance back-in-time an entity is able to travel from a given moment, and the foward-in-time, or ana boundary is the distance forward in time an entity may travel and still reliably be able to get back. Note that an entity can travel much further forward in time using relativity but is at risk of becoming trapped.

The center of the SoFT is called the Wells Point and is the point around which an event involving a time traveling faction like the Virgonians or Hunger can be considered to mainly exist. E.g. If the Elysium Cold War begins in 2800 AD, that is where the Wells Point will be and where most of the activity of the war will occur, but activity will also occur before and after that point proportional to the ease of travel.

A diagram of the relative levels of ease of traveling to different points in time from the Wells Point. The green plot shows the SoFT, the region of the timeline that can be freely traversed ana and kata within using antisaggitarian and/or relativistic time travel. The blue plot shows the region of the timeline that may be traversed ana using only relativistic time travel.

A given faction's SoFT will tend to spread wider into the future as better time travel technology develops. The rate at which time travel technology develops can be measured in years per year (also know by the unit Browns), i.e, how much further back an entity can travel back per year. If a technology develops at a rate of 1 Brown, that technology is said to be katostatic because the forward-drift of the center of the SoFT due to time simply progressing will be equaled by rate at which the spread increases, meaning that the furthest point accessible in the past will always be accessible, at least for as long as development remains katostatic. Katocontractive development occurs at a rate of <1 Brown and will lose temporal ground in the past, whereas katoexpansive development occurs at >1 Brown and will gain acess to more and more of the past as time goes on.

Wells Points

Wells Points are a chronographical phenomenon analogous to the "center" of a city or battle, or some other spacial event/place. Every temporal event has boundaries of the most distant relevant point in the timeline both forward and backwards these are called the ana and kata terminals of the event.

Wells Drift

A Wells point may be shifted slightly by better time travel technology developing in the future. The rate at which time travel technology develops can be measured in years per year (also know as the unit Browns), i.e, how much further back an entity can travel back per year. If this rate is greater than 1 Brown, the Wells Point will usually be found not at the event it corresponds to, but slightly shifted forward in time. This is because of the advantages; the better time travel tech the at this future point may allow the same or greater kata mobility but also have the benefit of all other technologies being better. E.g. if the Hunger can only just reach a planet in the ancient past of Pristini from the year 2000 AD and decide to destroy it, the Wells Point may occur in the year 2300 AD because developments in tech allow them to still reach the planet even though it's 300 years more distant, but their weapons tech has gotten better. This appears from inside a time traveling faction as the faction simply waiting a few centuries to accomplish a task because they know their tech will be better. This temporal behavior phenomenon is called Wells drift.

Temporal Mechanics

Time travel operates under a multiverse framework where every event creates a different universe, called a timeline, depending on the outcome of the event. And entity from Timeline A going back in time and changing the outcome of an event from outcome A to outcome B will then continue to live in Timeline B.

This avoids paradoxes like going back in time and killing your own ancestor as you will continue to exist in a timeline where your ancestor is dead, but you're causation will be preserved because the timeline where your ancestor is still alive still exists, it's simply inaccessible. Neither faction in the Cold War have the ability to freely traverse five-dimensional space to access other timelines so their goal remains to ensure that they each exist in the timeline that is most favorable to them by the outcome of events that have already happened in the timeline they were originally from.

Timeline Classification

Nautrally, the universe will branch into more timelines every instant due to the thousands of events occurring. How similar two timelines are can be measured exactly in their Quantum State Divergence (QSD) which compares how different the value of the wavefunction of a given volume of space is in percentage (Called the %Divergence). This can be used to organize timelines into groups. Of course, the total wavefunction of a given region of space is impossible to calculate exactly, but the %Divergence can be estimated using complex heuristics and the immense computing power of something like a matrioshka brain.

The generic term for a group of timelines is a skein while the collective term for all timelines is the Fabric of Time. The first moment in a new timeline after it has diverged from its parent is called its basal instant. Timelines are classified into groups based on the %Divergence at their basal instants from their last common divergence point (LCDP).

Name %Divergence Threshold Skein Unranked Stitch <0.0000001% Seam 0.0000001 - 1% Thread 1 - 10% String 10 - 50% Ribbon 50 - 99% Weave 99 - 99.999999% Tapestry >99.999999%

This means that if the timelines change later to be more similar to each other, they are still classified by the original group as the %Divergence at the last common divergence point remains the same.

Timeline A and B are in different ribbons of time due to their >50% %Divergence. The later timelines A_2.4 and B_2.1 are also in different ribbons, even though their 17% Divergence would suggest they are only in different strings of time. This is because their LCDP is the basal instant of Timeline A and B

As %Divergence is specific to a given region of space, this also means that two timelines may be considered to be more closely related when a large amount of space is being considered (%Divergence is low) than when a small amount of space is being considered (%Divergence is high). E.g. A difference between two timelines of a planet existing or not is a huge %Divergence when only the star system is considered but a very small %Divergence in the context of a whole galaxy.

Temporal Strategy

Although energetically expensive, Essence-based temporal shielding also exists which tethers one to another time traveler in five-dimensional space such than if they end up in a different timeline, so will the shielded entity. For the entity this appears as if the universe is changing around them as they are pulled from one timeline into another parallel to the event-changer. This can be used to follow a temporal assailant into the new timeline they've created and possible change events again to undo the changes they've made. E.g. If a Hunger form goes back in time from Timeline A to destroy a planet in the Pristini Galaxy, entering Timeline B, a tethered Virgonian Seraphim could follow it into Timeline B and reconstruct the planet, creating a Timeline C from a slightly later point in B. This timeline C would be identical for all intents and purposes to Timeline A.