Editing GURPS Infinite Worlds (section)

== Parachronics for Dummies ==
The Infinite Worlds setting draws heavily from H. Beam Piper's "Paratime " stories; instead of going backwards in time and potentially screwing up your own future, you physically travel to a parallel universe that just happens to closely resemble your own at some point in the past. This is great for /tg/ purposes because it instantly removes all of the headaches that happen when you give players access to time travel. No leaving yourself the solution to the adventure Bill & Ted style. No hour-long arguments about player characters meeting themselves or "why can't we shoot Hitler?" bullshit. Access to parachronics is strictly controlled, so the party can't go AWOL to find the timeline where genetically engineered catgirl slaves exist instead of playing your campaign.

Parachronics is the means of sending matter from one parallel universe to another within a certain "range". The parallels accessible from parachronics are (almost) all copies of the "prime" universe (called Homeline) where alternate quantum states caused history to turn out slightly differently. In (almost) all of these alternate worldlines time also flows a few billionths of a percent slower, explaining why they're "in the past" compared to Homeline.

=== Getting there ===
Parachronics-accessible timelines are clustered into 10 "quanta" in higher-dimensional space. Homeline is in Quantum 5 and can access worlds as far out as Quantum 3 and Quantum 7; the closer the timeline is to Quantum 5 the easier it is to reach.

To send something into another timeline, you can either use a parachronic projector that effectively teleports matter one way or a conveyor that acts as a "time machine" within the same quantum but needs to be boosted across quantum levels by a projector. Parachronic travel effectively telefrags anything at the destination. Parachronic travel also requires a lot of power; conveyors stuck in a strange time without power have to locate a windmill, steam engine, or convenient lightning storm in order to get back.

=== Timeline Types ===

* '''Empty:''' Either mankind never evolved, hasn't evolved yet or went extinct. Mostly used for colonization, resource extraction, waste disposal and trophy hunting.
* '''Temporal Echo''': Identical to Homeline history, just running behind by a certain number of years. They exist so GMs can run "history has gone wrong, go back and fix it" adventures without dealing with actual time travel. If you change the course of history in an echo, there's a chance the timeline will change quantum levels (potentially stranding you) or "disappear" entirely.
* '''Anchor:''' An anchor is an echo that doesn't shift around if you send it "off course". Infinity and Centrum usually buttfuck these timelines quite roughly since nobody has to worry about a stray shift marooning their own agents.
* '''Parallel:''' Actual alternate histories. The differences that make a world a parallel range from "Pete Best never left the Beatles" to "the Norse never Christianized and [[Vikings]] rule America" to "Godzilla is real and the Pacific Rim has to deal with giant monster attacks every few decades." So-called ''high-inertia parallels'' are parallels closer to the Godzilla end of the scale that still have recognizable cultures.
* '''Hell World:''' [[Death World|Death Worlds]]. Causes range from super-pandemics to World War III to the stars becoming right and [[Cthulhu]] eating everyone. Sometimes they can be cleaned up and used as empty worlds but usually they're better off being left alone, after the PCs try to find out what the hell happened of course. This is also one of the only worlds where Infinity is willing to flat out conquer any survivors of the original apocalypse, since it's frankly an improvement over slowly dying to whatever made it a hell world in the first place.
* '''Puzzle World:''' Timelines that are just ''weird''. Printed examples include Möbius, which is somehow Quantum 4 and Quantum 7 at the same time, and Rustic, where [[Medieval Stasis|harnessing electricity is impossible.]]