# Wanted: a working method to quantify divergence.

## Recommended Posts

Hi guys, still writing my time travel novel. Something has came up though, and I know we don't have much time left so I thought I would ask "the heads" and get some opinions...

My question is..how would one go about measuring divergence?

To give some context , in my novel you have a set of time travellers who are trying their best not to change anything , and are also constantly checking their known version of the present (time that they are inhabiting) against a data base of historical events already compiled that they bought with them....

It seems to me this will become an exercise in statistics..and then, if you did find an event which was different, how would you quantify the effect? How could you use that knowledge to predict what the consequences might be further down the line into the future? I know that computer models predicting outcomes do exist because they use them in wargames ..what algorithms do these programs use?

##### Share on other sites

Since it is fiction to start with, there are no holds barred. You just have to make it believable.

Start with wave theory. Postulate the existence of time waves, orthogonal time waves, and opposing time waves to either of the previous categories. That would allow you to have standing waves of time. Many things in nature are held in place by standing waves. Divergence could then be defined as orthogonal or sideways travel to parallel timelines. Since we would exist in our own location within a standing time wave, we would start with the amount of energy needed to jump to the next trough in an adjacent low spot in the time wave. Call that .o1% divergence. So 2.0% divergence would be 200 wave troughs in one of 4 possible orthogonal directions. Make the postulate that time also has 6 possible directions just like space. You could label the available parallel timeline directions as A, B, C, D, and +,- for forward and reverse.

Of course I don't have the number for the highly classified frequency of the time waves. And the amount of energy needed to jump to the next low spot is also classified. So you might let your readers know that there is some information that you legally can't release.

##### Share on other sites

Entropy might be a good source for divergence.

Everything you do...when you breath...or that everyone does...eating, drinking...or that every "thing" does... when a rock slips loose and rolls down the side of a mountain, changes the entropy in the universe. We can determine entropy by direct measurement or, more commonly, by calculation. The simple formula is Delta S = q/T

S represents entropy, Delta S = the change in entropy, q represents heat transfer, and T is the temperature (25 deg C is the common reference constant[sTP standard temperature and pressure]).

The change in entropy (ΔS) was originally defined for a thermodynamically reversible process as

Delta S = \int \frac {dQ_{rev}}T (this is how the formula came out from copy/paste. I don't know how to enter calculus notation except with a pencil. Old school I guess.)

which is found from the uniform thermodynamic temperature (T) of a closed system dividing an incremental reversible transfer of heat into that system (dQ). The above definition is sometimes called the macroscopic definition of entropy because it can be used without regard to any microscopic picture of the contents of a system.

This is what time travel, into the past, would need to entail.

You can define the reversible process for TT backward like this;

In thermodynamics, a reversible process -- or reversible cycle if the process is cyclic -- is a process that can be "reversed" by means of infinitesimal changes in some property of the system without entropy production (i.e. dissipation of energy).[1] Due to these infinitesimal changes, the system is in thermodynamic equilibrium throughout the entire process. Since it would take an infinite amount of time for the reversible process to finish, perfectly reversible processes are impossible. However, if the system undergoing the changes responds much faster than the applied change, the deviation from reversibility may be negligible.(hence the purpose and design of the time machine) In a reversible cycle, the system and its surroundings will be exactly the same after each cycle.[2]

In your own words of course.

Poincaré recurrence theorem

Ergodic theory

kaon decay

CPT symmetry

Euler–Lagrange equation

Include some exotic looking calculus formulas relating to each.

Remember... "If you can't dazzle em with brilliance...baffel em with BS"

After a copious amount of BS explain how divergence is the measure of the difference in entropy as "already measured" in the travelers time line to measurements collected during the incursion into the past. Use the Poincaré recurrence theorem to explain away minimal insignificant changes.

##### Share on other sites

Thanks muchly guys! Neither of these fits my bill but they have set me off thinking....as far as my travellers reversing entropy to get back in time that isn't what's happening, as I envisioned it...instead it is more that a copy of a person is made back in that other (past) time, which becomes their present for as long as they are there. Because that rewinding of actual matter to reverse entropy would indeed be impossible..like peeling a banana then trying to seal it back up again

##### Share on other sites

Might look to the Television show " Quantum Leap ". Don't know if they ever explained how their system worked, however, the main character shifted from one time period to another , but had contact with a " parallel hybrid computer " that calculated the probable outcome's of events based on "Sam Beckett's" actions.

The Premise section explains the plot somewhat on Wikipedia.

Now, if there was a "parallel hybrid-divergence computer" that calculated the divergence percentage of any particular dimension compared to another - you wouldn't actually have to explain "how" in depth, just something that the computer is capable of doing.

Also might look at "Foundations" written by Isaac Asimov for possible inspiration. Creating an adaptation of the "psychohistorians" and the "mass effect" for use in your writings.

Thanks Kerr!

##### Share on other sites

• 4 weeks later...

the only way to even attempt to begin to quantify divergence (as I understand it) is to have an entity that somehow was unlocked from linear time and was able to maintain original memories from the unchanged timeline. Then the person would have to be able to perceive divergences, so obviously the big obvious things that they would notice would be political changes, major changes in real estate development, like perhaps a new skyscraper that seemed to suddenly appear to them that was never there before in the original timeline. The likelihood that the folks wanting to measure divergence just increased exponentially. But this entity, let us call them the Auditor, would have to be willing to take part in divergence measurement activity, so something would have to be in it for them.

##### Share on other sites

That's an interesting idea for a story in itself, Auditormaterial. I can't see it fitting into my current story, but thanks anyway.

##### Share on other sites

...what algorithms do these programs use?

Better questions are: "Diverge" from what and ; what is the definition of divergence in this situation?

You have to know information about both frames (universes) in order to compare and contrast them. How can you compare the state of our universe to the state of some other universe without being able to observe it?

Even in our own universe our knowledge of the most recent events is limited to, outside the Solar System, 4.3 light years distant (Alpha Centauri). Using our Solar System (5 cubic light years volume) to measure how much our universe diverges from what we anoint to be our alternate universe (which would have a diameter of 40 LY thus a volume that is at least 2.7 x 10^32 cubic light years) might be a bit too small a "sample population" for valid comparison.

So figuring out what metric to use puts the cart before the horse. You have to figure out the question you want to ask before applying a system of comparison to the situation to answer the question.

In the end, however, the probable answer to the methodology is really, really ugly - Gauss' Theorem. It's a vector calculus used on vector fields.

About divergence: Stating it as a constant would be the wrong answer, i.e. "the divergence of this universe from some other universe is 2.5% - in this universe she has green eyes, in the other blue". It's a vector field. Vectors for changing states implies acceleration. Either the direction of the change is changing, the magnitude of the change is changing or both are changing. The rate of divergence accelerates over time; it's a second order derivative (the rate of change of the rate of change). "She" (and everyone else) is unlikely to exist at all in the other universe.

##### Share on other sites

(again...) stochastic heuristic algorithms are the only kind remotely possible of statistically forecasting quantification of divergence, going forward, if you were to estimate impact from event-level changes. Assuming Earth is the only portion of of the said universe that we have to be concerned about permutations/divergence is sufficient, this reduces the data quantification requirement immensely. Furthermore, select ethical criteria reduce divergence quantification requirements again by orders of magnitude. The real question, one I have an idea about, but no practical way to test, is how to unequivocally maintain, without risk of corruption, a standardized multiverse-independent "log" of the relevant subset of data to measure divergence against.