This whole multi-dimensional stuff.

Anyone else into that sorta fringe science theory about infinite dimensions branching out with every possible outcomes of events? I think it's interesting, but I don't really see the reality of it.
I believe that everything's cause-and-effect. Like if you roll a di, there may be a probability of it coming up as any side, but it -can- only come up one way depending on all the factors ranging from its weight, the way it was tossed, etc. The same mechanic works for our brains, so any decision a person makes is the only one that they could have given enviromental and genetic factors.

Also, if there were branching dimensions, I'd see it more as a near-infinitely many outcomes. Given a fixed amount of space, matter, and time, there's only a near-infinite amount of permuations.

Still interesting though; sci-fi shows like Noein and Fringe take advantage of the idea. I like to day-dream about alternates of myself. Anyway, that's what I'd like the topic to be about if know one has anything scientific to add; what would your alternate dimensional self be like?

Well, the idea is that there's a branch for each and every possible event. Let's use your di example. There are six possible outcomes to rolling that di. Theoretically you'd have six different branches split when you throw the di, one for each outcome.

Well, that's what I was trying to refute: there wouldn't be branches because the di can only land one way. There's probabilities for it landing on each only because we couldn't calculate all the factors, making it impractical to know the outcome, but not impossible.

Multi-dimensional theory assumes that a di landing on one side is just as possible as it landing on another, so there's a dimension for each. I say that since only one landing is possible, there's only one dimension. Probability is just a number we use to organize outcomes when we can't make a prediction because we can't figure in the complex factors.

The human mind has the most complex of those factors- that's what makes it seem like we can make unpredictable decisions.

I don't believe in alternate dimensions based on the decisions made and not made, nor alternate outcomes. If there were other dimensions of the sort you refer to, then time travelling would have been possible lol. I think it was completely disproved in fact.
Once something happens, that's it. Any other outcome is disregarded and well, 'life happens'.

The possibility of time travel and dimensions aren't that related. However, multiple dimensions would be necessary for backward time travel to prevent paradoxes, yes. Forward time travel is possible, though. That whole relativity thing from your physics class.

Anyway, like in my first post, the plausibility of fringe science isn't what I was bringing up, I just think it makes for a good sci-fi show.

Time travel is not impossible, the faster you go, the slower time travels around you, this was proven by putting relatively short lived particles inside of the LHC and accelerating them to near the speed of light. Instead of living for a certain amount of seconds, the particles lived quite a bit longer, in fact almost double their lifetime IIRC.



I don't see how you could travel to the past via the use of other dimensions, only that you could travel to a dimension where certain events had different outcomes. I wholly believe time-travel to the past is entirely impossible, because you would literally need to reverse the flow of time in order to do so. Then again, perhaps time travels at a different pace in other dimensions, meaning you would, in a way, be able to travel to the past, which would still technically be considered the present.

First reply: that's what I meant by forward time travel. From light's perspective, speed is instantaneous. It's impossible for any amount of matter to go that fast because you'd need an infinite amount of energy to do so.


Second reply: I didn't mean multi-dimensions as a -way- of time travel, only as a solution to a paradox. If you were to travel backwards, you'd be affecting somebody else's future.


I once did a thought experiment about backwards time travel...
Rather than traveling faster to slow time, if you were to slow down relative to the fabric of space you'd be going faster in time than everyone else. Still wouldn't move backwards though: if you were perfectly still compared to space fabric you'd be traveling the fastest through time and everything else would simply stand still.

well, i think that in every dimension, each has a separate look on to it, remember the play called "flatland"? where in the people in that dimension are shown as simple lines. according Professor ed written of the institution for advanced study in Princeton, new jersey, says that there are multiple dimensions, but each is concerned by spatial figures:
dimension 1: length
dimension 2: width
dimension 3: height, mass, and weight (reality)
dimension 4: time
dimension 5: space
and etc. each dimension displays different versions of our selves and different versions of our actions, same as rolling a die would reveal different statements in regards as to how the die was thrown, what time it was thrown, the die's velocity, the angle of the die, the weight of the die and finally the die's mass or how far away is the die from the planet's core. Prof. ed written predicts that there are 22 dimensions

What about multi-dimensional theory in regards to string theory? The other dimensions are only for the sake of allowing matter to exist at all.

Well there are 2 "multidimensional" things going on here.

One is about there being more than 3 spatial dimensions in *this* universe. The other is about there being multiple *universes* each one with its own 11 spatial dimensions or so.

The word "dimension" became sinonymous with "universe" in the 80's and that baggages carries to these days but the concepts are not interchangable. Different universes are alternate realities. Spatial dimensions are just alternate directions you can move in.

We move in strictily 3 dimensions, but there is a chance that small particles can move in more directions than those. That could explain how some particles can instantaneously jump from one place to another, they may be simply moving normaly in directions we don't know of.

Also, it may be that particles constantly switching between two or more states are simply moving linearly across a small dimension so that what looks like quark alternating between chromodynamic charges is in fact just passively drifting in directions we don't know of.

An those are only spatial dimensions, some string theories predict 2 temporal dimentions (two timelines perpendicular to each other) that could explain some non-local events.

That is COMPLETELY independient to the many worlds interpretation of quantum mechanics. The thing with quantum mechanics is that there is a set of phenomena that are, by all accounts, completely random. Random is not good. Random usually means that we don't understand the circumstances. Einstain's objection to quantum mechanics is that there are hidden variables affecting quantum events and that if we were aware of them we would see that the events are not random. But we haven't found them, and we have looked pretty damn hard for them.


The copenhangen interpretation is that we shouldn't worry about it and just move forward AS IF they were completely random, and many believe that there are still hidden variables. The many worlds hypotesis tries to fix this by suggesting that maybe the randomicity is not in the event but the observers.

So it's not really true that a given atom has a 50% chance of decaying this very
second. What really happens is that the universe splat in two universes, one where it decayed and one where it didn't, but for observers it looks like only one or the other event happened.

That's what the many worlds hypotesis does. It explains away apparent randomiciy at the expense of alternate, unobservable universes. But it has nothing to do with the extra spatial and temporal dimensions of string theory, those, if real, are here and are accesible to us with the apropriate instruments.

And of course there is the crack pot hypotesis that there may be beings in *this* universe who are only aware of those extra dimensions just like we only are aware of the our own 3 dimensions + time. But unlike alter-universes which are just like our universe but with a different history, those alter-dimensional realms would be entirely too different and may be completely devoid of life, just like this realm is nearly devoid of life and nearly devoid of anything in general.

http://en.wikipedia.org/wiki/Schrödinger's_cat
I sure love quantum mechanics

Hopefully you understand that we all are aware of Schrödinger's thought experiment. Then a better link would be this: https://www.thinkgeek.com/product/e9cb/

This is an awesome person.

To what extent is gravity understood? I was under the impression it was never fully understood and unified with the 4 forces? Does it fall into the category of unknown and by extension random as far as we know? I'm wondering how far our understanding of it goes, and if there is random in the universe can it stand as a source.

Gravity is the result matter has on space fabric. As I understand it, matter pulls in space fabric, there by pulling other matter into it aswell.

Its mass that creates gravity and that matter is but a factor (I'm not sure myself). Example: of white dwarfs or neutron stars.
Http://en.wikipedia.org/wiki/Gravitation
I doubt I'd fully understand most of this (if I had gone through with reading it all, what I have read is confusing) but I think the first paragraph explains where I am lost.
Http://en.wikipedia.org/wiki/Fundamental_interaction
"The four known fundamental interactions are electromagnetism, strong interaction ("strong nuclear force"), weak interaction ("weak nuclear force"), and gravitation. All are non-contact forces. With the possible exception of gravitation, these interactions can usually be described in a set of calculational approximation methods..."

I've been meaning to read up on this, general relativity, and Equivalence principle, among other things, but every time i try i either become lost or end up over encumber (opening link after link) till my head hurts. I feel i need prior teaching to read most of them. ~sigh~

Edit, I don't understand what exactly is included into space fabric, everything that we know of that exist in the known universe?

Just to add to EggManZ and hadnochoice replies, the amount of space seems to be infinite and ever spreading (according to some theories), while matter/energy is constant. According to this in our Universe somewhere at some point there will be the same die rolling but with a different result. That does not concern alternative Universes and/or additional dimensions. It will all happen in our Universe, unless cold death happens before (if you follow that theory).

We cannot travel between those many worlds or anyhow communicate with them, so to us, there is no difference, whether there are many worlds or not (like hadnochoice stated about the observers).

A bit on a string theory as well: it is difficult to create tools to test that theory, because strings are so small (see Planks length) so if it turns out that strings are "shorter" than Planks length we will never be able to directly measure them regardless of technology at hand or so theory goes.

I'm not sure, but I think you're confusing two separate, although very closely related, ideas. The idea of 'multi-dimensionality' and 'multi-universality'.

Most people consider extra dimensions to be like what Plato considered in his Theory of Forms. That in a separate dimension there is a version of you doing something slightly different in an infinite number of ways, but one of those was the 'real' you or the 'archetypical' you. That's actually what most people in my field of work would consider multi-universality, and very few really believe in it, other than for making interesting conversation.

Multi-dimensionality, or extra-dimensionality, as I prefer, is the idea that objects and virtual particles in our observable dimensions aren't limited to the ones we can outwardly observe.

Here's an example. If you know much about modern physics you probably know that electrons are impossible to track, i.e. to know where they are and what they're doing both at the same time, however we can calculate a probability of where they are at any given time. Said probability is known as it's wave function, and is infinite in scope, so an electron of the carbon atom at the end of your finger has a probability of being at the far side of the universe in the next moment, without actually travelling. Now, this is seemingly impossible, as we have the universal speed limit of 300,000,000 ms-1, or the speed of light. However, even if you take one extra dimension, say one that only leptons(electrons) can travel in, you have the means to get from A to B without breaking down the laws of physics as we know them.

Usually this brings up the question "Well, how many dimensions are there?". Most people that I've spoken to, and what I've gathered from my own research, dilly-dally between 7 and 11. This is purely because of the maths involved. When you reach 7 dimensions, the maths used to calculate it is not only very difficult, but also starts to create numbers large enough to contradict constants we use every day, light the speed of light and Planck's constant. However, these could easily just be things that are only constant in the four dimensions we observe and could easily be scalable with each dimension you add in. 11, however, starts to make small of pure constants, like pi and the fine-structure constant, so as far as we're aware, 11 is the absolute maximum.

I am aware indeed of Heisenberg's uncertainty principle.

To point out about the cause-effect principle, let's just put the wave function collapse in here as well, to mention that that what happens when the die rolls without us observing is that it actually is in superposition of all the 6 possibilities and only when we look at the result the function collapses to one "solution".

Well, that is a lot of science here, someone needs to put it all together...

Hmm, basically if a tree falls in the woods. Not quite. If you take the die, and it has six static outcomes, and you 'observe' it's probability of each state. That 'observation' of knowing that it can be in one of six states is the most information you can have without checking to see what it lands on. You could say that as soon as you know the die has stopped that would be another observation, so now you know it is no longer in the previous superposition of states and has, in fact become normal. To be honest though, there isn't much behind wave function collapse other than to explain wave-particle duality, at least not yet.