Today, Tomorrow and Yesteryear: Time Travel

Technologically, Time Travel is quite simple. It involves bombarding a core of [REDACTED] with a steady flux of [REDACTED]-[REDACTED] until it [REDACTED], then letting it [REDACTED] for [REDACTED]. Nothing that couldn't have been invented with the materials available during [REDACTED]! Now, aiming is a little more complicated. The best technology known to this day requires a the full [REDACTED]of a [REDACTED], and a [REDACTED] to improve [REDACTED]. As you may imagine, such [REDACTED] may only be found [REDACTED], which understandably does tend to limit the number of Continuum Indirections in this Continuum – and from there, the number of Time Travelers!

Also, while most people can enter a Continuum Indirection without problem, please make sure to visit a doctor every few trips, to ensure that you do not experience Space·Time Allergy, or worse, the Space·Time Rejection Syndrome.

Where can I go?

Well, pretty much anywhere you want. With an up-to-date Continuum Indirection, nearly all of Space·Time is within your reach. Continuum Indirections travel thanks to the [REDACTED] effect, which means that you can reach Space·Time coordinates even if a traditional 4D path would have taken you through solid matter. The travel itself may take a few seconds – or, in some cases, a few minutes – et voilà!

Now, there are some limitations to where your Continuum Indirection can take you:

Most Laws of Physics degrade seriously when approaching either the Big Bang or the Big Crunch. The second corollary of the Law of [REDACTED] determines that a Continuum Indirection may not travel before the Afterglow (any time between the Big Bang and BB + 375,000 years) or after the Black Density of the Universe reaches approximately 10^-16 (also known as Big Black Horizon).
For the same reasons, Continuum Indirections may not travel to or through Smaller Bangs and Smaller Crunches.
Similarly, the seventh corollary of the Law of [REDACTED] clearly determines that Continuum Indirections cannot escape from a High-Gravity Curvature, such as the close proximity of a Black Hole, the inside of a star, or the heart of a planet. For these reasons, your Continuum Indirection is programmed to automatically avoid such Space·Time coordinates. Not that you would survive in one, anyway.
Technically, a Continuum Indirection may materialize at the same coordinates as a body, including most gases, liquids and solids. The Continuum Indirection will displace this body, as proved by [REDACTED]'s corrolary of [REDACTED]'s well known Law. However, while displacing gases, liquids or plasmas is generally mostly safe, displacing solids tends to pulverise them. All Continuum Indirections are equipped with advanced [REDACTED] that strongly decrease the probability displacing sentient creatures. However, caution is suggested.
Sufficiently dense Gamma Meson bombardments have been known to play havoc on the [REDACTED] of Continuum Indirections, which may theoretically end up with your Continuum Indirection landing at Space·Time coordinates slightly different from those you had in mind. However, don't let this scare you. The probability of encountering a dense Gamma Meson bombardment in the entirety of Space·Time is so infinitesimally small that you could spend millenia traveling with your Continuum Indirection without encountering a single one!
On occasion, Continuum Indirections have been known to travel to and from alternate universes. While this is actually quite easy to do, experience shows that it is extremely hard to do on purpose.

What does my Continuum Indirection look like?

Since you are a Ronin Time Bureaucrat, the aspect and features of your Continuum Indirection depends a lot of where it comes from, and how you have customized it since you, er, eloped. You may find information on standard Continuum Indirections in chapter Here, There and Right Behind You: The Bureaucracy.

A wide host of different technologies afford of Continuum Indirections that look like, well, pretty much anything. It may be a spaceship as well as a a bathtub, a restaurant as well as a book, or a map, or a corridor or a sports car, or, well, did we mention pretty much anything? And yes, it may be larger on the inside, although it doesn't have to.

Many – though not all – Continuum Indirections are also designed to allow communications through Space·Time. There are, however, dozens – if not hundreds – of incompatible Space·Time communication technologies, not counting the local space-communication techniques developed by natives, which explains why having a phone conversation through Space·Time is generally much harder than simply walking to discuss face-to-face with your interlocutor.

It has been noticed that, regardless of time and space, the so-called Time Plebeians (aka non-Time Travelers) do not seem to care all that much about the appearance of a new shop, piece of art, building or even city, so after a time, Indirection engineers gave up on attempts at camouflage and just rolled with it.

Paradoxes and Pocket Continuums

Many things can happen in time without any kind of consequence. Do you wish to teach the 5th Symphony to Beethoven? Not a problem. Step on a butterfly? Most likely not a problem, either. Give the Mona Lisa a moustache while Leonardo Da Vinci is asleep? Chances are that he's going to fix the issue tomorrow morning. Kill baby Hitler or your grandfather? Ah, that might be a problem. Or then, it might not.

This has been formulated as the Law of Observable Contradictions.

An action by a Time Traveler (or a group of Time Travelers) increases Paradox if and only if it causes a contradiction with respect to whatever that Time Traveler (or group of Time Travelers) has observed in their subjective past.
However, if the apparent observable contradiction that may be explained reasonably enough to be waved away will cause little-to-no Paradox increase. More details on Explanation will be discussed in chapter Where, When and How: The Rules.
Too much Paradox will eventually cause the local Continuum to fold into a Pocket Continuum. That is not good.

Example:

Time Traveler Tom just shot the Big Bad Masked Man, without realizing that, behind the mask, Big Bad Masked Man was also Grandfather Gerry, before he met Grandmother Greta.
Apparently, this is an Observable Contradiction. If left untreated, it will damage cause Paradox, damaging the Continuum.
Paradox is bad. Time Traveler Tom doesn't like Paradox. So Time Traveler Tom will attempt to Explain the Apparent Contradiction.
Time Traveler Tom argues that Grandmother Greta has always been a compulsive drunk, who had sex with just about any stranger. She was also a compulsive liar. So, there are very good chances that Grandmother Greta had no clue who Time Traveler Tom's grandfather really was, and just used the picture of a random man.
Time Traveler Tina adds that she volunteers to slip that picture to Grandmother Greta, at some point in the future.
Finally, Time Traveler Tom adds that he's pretty sure his mother never asked question about her father because Grandmother Greta had always told her that Grandfather Gerry was a violent and unstable man.
Is this a sufficient Explanation? Let's hope it is, because otherwise, you might end up with a...

Pocket Continuums

As it turns out, Observable Contradictions can very well exist in the universe, although generating an Observable Contradiction is seldom in your own interest:

A large enough Observable Contradictions may cause the creation of a Pocket Continuum.
Naturally, a Pocket Continuum will tend to fold upon itself and vanish very quickly, with everything and everyone who happened to be in the Continuum at the time.
You may wish to remain in this Continuum, in which your parent was never born, nor were you, but unless you find a very good way to strengthen it, it will quickly implode. You may survive the implosion if you are in your Indirection at the time.
If you really, really want the Pocket Continuum to survive, you will have to strengthen it. If you can somehow lure many Time Travellers (perhaps by importing a whole section of the Time Cold War?) into your Pocket Continuum, it will eventually become the Main Continuum – or perhaps a Main Continuum, experiments on the topic have never been quite conclusive.

Example:

Let's assume that Time Traveler Tom and Time Traveler Tina never managed to Explain the Grandfather Gerry Paradox.
The Continuum has just split.
In the Main Continuum, Grandfather Gerry was never killed, Time Traveler Tom's ancestry was never doubtful and both Time Traveler Tina and Time Traveler Tom entered their Continuum Indirection to travel through Space·Time. Unfortunately, they simply vanished and never arrived. They may have been reported Missing In Space·Stime.
In the Pocket Continuum, Grandfather Gerry was killed by Time Traveler Tom. Time Traveler Tom was never born, but he's a visitor from a different Continuum. Time Traveler Tina was born normally, assuming that nobody killed her Grandfather (Time Traveler Tima's Grandfather Georges says hello, so, yes, he seems to be alright, also, he wants to know when he's going to have great-grand children, sigh).
The Pocket Continuum is really, really unstable. Very soon, it's going to implode. Let's hope that Time Traveler Tina and Time Traveler Tom can manage to find a way out and back into the Main Continuum!
Or perhaps this had been Time Traveler Tom and Time Traveler Tina's plan all along? Maybe they do have a plan to consolidate the Pocket Continuum and get it to replace the Main Continuum? Space·Time will tell...

Note that small enough Observable Contradictions will not immediately cause the creation of a Pocket Continuum. In fact, small enough Observable Contradictions may even be Bandaged in such a way that the Continuum will manage to heal. However, an accumulation of unbandaged small Observable Contradictions is just as bad as a large Observable Contradiction. More details on Observable Contradictions and Bandaging them will be discussed in chapter Where, When and How: The Rules.

Help thyself

One of the perks of traveling in Space·Time is the ability to help oneself throughout the difficulties of life. Consider the latest meeting between Time Traveler Tina and Doctor Devil. Remember how Doctor Devil fired his Devilray of Devilry at Time Traveler Tina, hoping to turn her into a pile of cinders? But no, Time Traveler Tina did not die, for she received the surprise visit of Future Time Traveler Tina, who pushed her away at the last moment, avoiding the certain doom that would otherwise have befallen her!

Remember how Time Traveler Tom was trapped into the Serpentine Schrödinger Sinuisity and could not find his way out, because he did not have the schematics that would let him disarm the quantum clock that laid at its heart? Fortunately, Time Traveler Tom opened a drawer, only to find a sealed enveloped at its name, containing all the necessary information, hence saving Time Traveler Tom and the universe. It was later proven that the envelope had been left there by Future Time Traveler Tom for the sake of his Past Self.

The ability of Time Travelers to help themselves through time has been thoroughly studied and formally proven to cause no Paradox, as long as the following conditions are met:

The Time Traveler must remain physically able to help their past selves in a manner that does not contradict the observation of Past Self. In particular, the Time Traveler must still be alive.
Future Self and Past Self may remain at most a short instant at the same Space·Time location, as anything else becomes messy.
It may not be used too often.

More technical details on Death Defying Space·Time Travelers and their ability to Help Themselves (and the limitations thereof) may be found in chapter Where, When and How: The Rules.

Killing off Bureaucrats

An important consequence of both the Law of Observable Contradictions and the ability to Help Themselves is that Time Travellers (and people aware of Time Travel) tend to take measures to avoid killing:

anyone in their past;
anyone who might be a Time Traveler;
anyone who might somehow interact with their past;
in particular, themselves.

That's because any such death has a tendency to snowball into an Observable Contradiction that may end up being very hard to Explain or Bandage. This does not mean that Time Travelers (or witnesses) never die in Space·Time. While a Time Traveler will be much more likely to use, say, sleeping gas, manipulation or brainwashing, than a gun or a tank full of sharks, they may have planned ahead on how to get that death to stick – for instance, Time Citadels of the Time Brigade are fully stocked with Perfect Polymorphic Provocateurs, designed specifically to morph into their victims, hence Explaining many Observable Contradictions that may have been left by the Time Brigade.

Today, Tomorrow and Yesteryear: The Basics of Time Travel