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[Starver]

All prophecies need to be self-fulfilling, in that making a prophecy necessarily affects the future in at least a small fashion.

If it's a 'branching universe', then it need not.  But it in a self-consistent and pardoxless one it might be that the prophecy prompted the man to tell people that the airplane was going to break, and got the engineers to strip the 'faulty' engine, finding no fault, but introducing the fault that was to occur when putting it back together in disgust at all the time they wasted.

(This might be a more 'stable' time-line than one in which the Predict-o-Matic said anything else, because if it said "All's fine", nobody would catch the hijacker who planned to take over the plane, and if it mentioned the hijacker then they would have stopped him and the universe would also be inconsistent.  Thus the 'only' universe that was self-consistent[1] was one in which the above prediction and problem occurred.)

[1] Barring a whole lot of other non-paradoxical solutions, but for whatever reason this is the one the universe 'chooses' in this hypothetical scenario.  In another universe the infallible prediction machine might bring up the "Error 404 - Not telling you, nyah nyah-nyah nyah nyah!" error, but that would change more than just the plane's future, but also the Predict-O-Matic's.

[Micro102]

I find alternate universes to be very unbelivable, if there were unlimited different universes, wouldn't there be one with some form of lifeform that would have come to this universe by now? I mean if there are infinite amounts of universes.....

[ChairmanPoo]

On the other hand , there would also be an infinite number of universes to which no creature with trans-universe traveling powers (if such thing is possible; theorically parallel universes stay parallel) has ever gone.

[G-Flex]

I find alternate universes to be very unbelivable, if there were unlimited different universes, wouldn't there be one with some form of lifeform that would have come to this universe by now?

Not if they're actually distinct universes.

[Earthquake Damage]

Not if they're actually distinct universes.

Perhaps the definition of universe should include everything it can interact with, negating the whole idea of travel/communication between universes.

[G-Flex]

I'm pretty sure that, for all intents and purposes, that is the useful cosmological definition.

[alway]

Yep, it is. Alternate universes cannot interact with one another, and if I were to guess, doing so would have some nasty side effects.

Code: [Select]

C:\universe1.exe : fatal error C1083: Cannot open include file: 'fifthUniversalForce.h' No such file or directory.
C:\universe2.exe : error C2065: 'particle48' : undeclared identifierIt would probably introduce all sorts of linker and syntax errors. 

[eerr]

No, the paradox arises when there is a recursion unsolvable by the machine. An infinitely repeating loop of the same circumstances, induced by the machine itself. In the first two variants, the situation is resolved quickly enough - just one or two calculations on the same matter. However, the third case is complex as the user's reaction is too polar, and produces a different result on each subsequent recalculation. It's the same beer issue - You get one of the two replies, and either compels you to choose the path of the other. For a machine that's supposed to give an accurate answer, this would be unsolvable without some sort of failsafe behavior for such an occasion, which would end the recursion at the cost of producing a false reply.

We consider the giant measuring device computer to measure time as if it was never consulted. This necessity should easily be deduceable by a computer able to compute such computations.  It can then give the corrected version at a later date. Thusly, he would now be able to change his future from what it once was, to what it now will be.

The computer would also end up with two diffrent answers for the same future at diffrent points in time.

This also is a very good lesson about restricted range and nearsightedness as useful tools under specific circumstances.

[alway]

Even still, I would expect a recursive prediction to converge at a point. An 'ideal response' as it were. The first iteration would dictate the event, the second and so on would dictate the response. There would come a point at which the responses predicted would probably converge to the point where it would be pretty much determined. Especially if the output explained the reason for doing the dictated actions.

[sproingie]

Hari Seldon predicted that Hari Seldon would get mentioned somewhere in this thread.

[Starver]

Close current session by 259 0683
Open new session by 0800 0556688

Even still, I would expect a recursive prediction to converge at a point. An 'ideal response' as it were. The first iteration would dictate the event, the second and so on would dictate the response. There would come a point at which the responses predicted would probably converge to the point where it would be pretty much determined. Especially if the output explained the reason for doing the dictated actions.

Any Predict-O-Matic that does actually work within a universe that can be changed by the output of the Predict-O-Matic is what I'd term a 'flip-flop' one (or possibly one in which a new branch of time-line is created by the actions of the POM[1]).

It seems much neater to me (i.e. I have absolutely no proof) that the tapestry of time is laid out in a self-consistent manner, which means that any 'looping' threads are thoroughly integrated into their own 'historical' part of the warp and weft already.  'Tapestry time' is the length-wise direction, along which most 'threads of existence' occur, time-travelers (and time-looped lines of information) are represented by threads looping back and over into the 'past' parts of the tapestry (and there's nothing to stop a thread being a never-ending closed loop.

The external time, during which the tapestry is constructed, is 'meta-' to the tapestry's own form of time, i.e. anything that the universe-inside-the-tapestry 'experiences', and speculative in nature.  If there's a Universe-Weaver (sentient or otherwise) busy rearranging threads until it works out, it's not a proper stable universe until the threads are all settled by the rules the warp and weft require.  An "always was thus, and always will be" tapestry (no inconsistent versions actually being possible in the meta-space) is a possibility, apart from various philosophical objections you might have.

A stable/valid/etc tapestry is thus laid out, from start of time to its end, any loops being part of the weave, and anyone 'traveling' (i.e. beign part of) the loops "go back and do what they've already been back and done.  POMs derive their information from the loops[2].  POMs in a stable universal-tapestry therefore either:
1) Don't work, or are just lucky beyond normal statistical probability,
2) Do work, just are 'creatively misinterpretive' so that nobody can complain that they are wrong, or
3) Work perfectly, but only providing such predictions that can be given to self-support the future reality that the predictions came from (e.g. with that example where it helps set up the bungled inspection on the aircraft engine to create the problem it predicts).


A variation on 2 is of the "If you go into battle against your enemy, today, a great empire will fall!" variety.  Producing maxims that are true (and, in that case, in an unexpected way) if followed but don't reveal anything about the future if not followed.  (Whether you follow the advice or not might well be determinable, so a valid response could be any suitably portentous waffle designed to off-putting to the recipient, sending them down the null-change route, but with enough correlation with null-change events (sidelined due to ignoring) to make it look as if there could have been something in it after all, after the fact.

A variation on 3 is easily be one that says "Not telling you" all the time, on the grounds that anything it did say would invalidate causality and produce futures that weren't its own.  Which would mean its own future existence wouldn't be too extensive, even if it can 'prove' it knew about it, after the fact, but causality remains consistent.

IYSWIM.

[1] If the Universe sums up as zero in its energy/mass equations then creation of a new branch may not need anything as drastic as the complete collapse of the old branch, but otherwise I'd expect the whole (potential) time-line of the original branch just past the point of prediction to be deconstructed for its mass/energy complement to be used in the creation of the new branch.

[2] Given the computational difficulty/impossibility (never mind the measurement aspect), and the far from disallowed nature of actual time-loops, within physics, I'm plumping for POMs getting a 'history' from the future rather than deriving (or 'divining') the future from ever-outdated and inaccurate 'current' information.

[Neruz]

Oh great, we've gone from Quantum Mechanics to Temporal Discussion.


I did not think we could go into an area more full of ludicrousness and speculation than a forum discussion on Quantum Mechanics and the origins of the Universe along with multidimensional theory.

I was wrong.

[decius]

Again, from the FoTF thread:

Ya, that's the bit about the light I left off. When it comes to welding your flame might be hot enough to make plasma but if it won't conduct electricity and such you're not there yet. It takes a whole lot of fire to push the ratio of ions high enough that you've got plasma.

Well, it would probably be more convenient to test with a magnet.

What would be the difference in electrical conductivity and diamagnetism (paramagnetism) between a charged gas and a plasma? Is there even a meaningfull line between the two?

Close, with flame color. It's not ions regaining electrons, but excited molecules giving off a photon to lower the energy state of a valance electron. But, there is also visible radiation-effected color, such as your standard wood fire where the burning off of volatiles in the wood cause the characteristic orange flames. Going with the wood flame, you'll notice that it eventually becomes invisible: wood burns for quite a while once the volatiles are purged, appearing as red glowing embers.

If you don't have a Bunsen burner handy, your everyday butane lighter can show the effect quite well. At the very base, against the metal, you have a premixing zone that doesn't burn. Directly above that, you'll see a (likely very small) blue chemiluminescent zone. This zone is fuel-rich, meaning not enough oxygen to fully combust all the butane, and produces a lot of carbon soot. As you go further up the flame, the stoiciometric profile will go from ful-rich to fuel lean, increasing heat and causing the soot to burn. Once the soot is burning, it gives off visible radiation, overpowering the blue flame with its orange, hence being the color that would most likely first come to your mind when thinking of a lit lighter.

As for the acetylene torch, you're looking at an entirely different beast. I would assume you have an oxygen line, so you have a premixed flame instead of a diffusion flame. When the mix is proper--most likely at stoiciometric conditions, though not necessarily--your flame color should be based only on chemiluminescence. The temperature, however, has more to do with flame quenching than anything else. If you have the metal too far up the flame, it will absorb the energy of the flame before it can be used to complete the combustion of the unburned gases, leading to a cooler flame.

The acetylene mix is -almost- at stoiciometric ratios at the torch tip. acetylene burns in two easily distinguishable stages; the 'proper' mix is to have enough oxygen in the mix to complete the first stage, and then use atmospheric oxygen to complete the combustion. The highest temperature in such a flame is at the point at the tip of the primary flame- mostly because the flame gets -wider- further away from the mixing tip. Normal use does not prevent full combustion,

Certainly the embers of a wood fire are blackbody radiation; Probably the flames are a mixture of dust emitting blackbody radiation. Are you saying that red-orange flames are typically soot or dust emitting blackbody radiation?

[Nivim]

 I would like to ask Manae; how did you learn that without learning the scientific meaning of volatile? It's not the common meaning.

 Also, I didn't think combustion reactions had multiple stages like rust or the like. I thought it was just one activated complex that released light and heat. I don't recall if the order of the reaction comes into play here, so that's why I'm not sure.

[Manae]

In fuel terms, 'volatiles' is equivalent to 'impurities.' It covers pretty much everything that isn't hydrocarbons. Have a look at this diagram:

http://www.uow.edu.au/eng/pillar/images/about/coal_rank.jpg

It doesn't really explain the term at all, but you can get an idea of its use. Also, for that particular diagram, wood would be left of peat with an even higher volatile and moisture content, and bituminous coal gets further compressed to anthracite. Some more numbers can be seen here; this diagram is from a little past the peat stage to late anthracite. The top graph is, I'm pretty sure, the higher heating value.

As for combustion having multiple stages, you better believe it. The methane/air combustion mechanism has literally 279 reactions. And that's one of the simplest systems. Order is only important at some stages, and once the system is started radical species are produced and consumed incredibly fast.

Also, I can't guarantee this definition, but I believe for matter to be considered plasma it has to be completely stripped of electrons. In essence, it's just a nucleus cloud, and hot due to the energy required to get to that state.

For my education, I'm a mech. eng. grad student. I know "mechanical" doesn't exactly make it seem like combustion would be on my course list, but its one of those branches that are pretty important to us. I've had similar-level courses in it during my undergrad and grad career (different schools), though the undergrad course focused heavily on diesel combustion while the grad course was more general overall, thus deeper in some parts (such as solid fuel combustion).

EDIT: Oh, and going with the disclaimer on the first post, I'm also adding that, since this isn't exactly going to publish or getting peer reviewed, the content is not guaranteed to be correct despite my best efforts to be sure it is. If someone notices errors, let me know so I can look into it deeper.