x/0

#### qubit

##### Overclocked quantum bit
Even tho the "speed of gravity" seems to be infinite/immediate otherwise if gravity propogated with slower speed every galaxy would fall part.
Gravity propagates at the speed of light.

#### entropy13

lol at the posts about infinity

#### Drone

Gravity propagates at the speed of light.
Yes general relativity says so. But it's confusing just like a spooky action at a distance.

In Einstein's theory of general relativity gravitational interaction is mediated by deformation of space-time geometry. Matter warps the geometry of space-time and these effects are, as with electric and magnetic fields, propagated at the speed of light. In Einstein's theory of motion, matter acts upon space-time geometry, deforming it, and space-time geometry acts upon matter.
Actually gravity cheats. It acts immediately because of the curvature of space-time. And even tho its speed is finite (c) it acts faster than light. In quantum mechanics word "faster" means using a shorter route, not having a faster velocity. Cosmic laziness, Geodesic Lines, Non-Euclidean Geometry and all that jazz .... you know.

The speed of gravitational waves in the general theory of relativity is equal to the speed of light in vacuum, c. Within the theory of special relativity, the constant c is not exclusively about light; instead it is the highest possible speed for any physical interaction in nature. Formally, c is a conversion factor for changing the unit of time to the unit of space. This makes it the only speed which does not depend either on the motion of an observer or a source of light and/or gravity. Thus, the speed of "light" is also the speed of gravitational waves and any massless particle. Such particles include the gluon (carrier of the strong force), the photons that light waves consist of, and the theoretical gravitons which make up the associated field particles of gravity (a theory of the graviton requires a theory of quantum gravity, however).
To get the answer we need to know all the theories: General Relativity, Special Relativity, Quantum Mechanics, Quantum Gravity Theory, Theory of Everything, M-Theory, Expanding Space-Time Theory, Supersymmetry, String theory (D-Branes), Unified field theory. Unfortunately the current status of all these theories is incomplete.

for our universe it would be:

x1^2+x2^2+...+xn^2 = r^2, where n is the number of dimensions that the universe really has and r is a constant yet to be discovered.

Now to complicate things even more, I don't think the universe would be an sphere (remember what I really mean by sphere), but some kind of elipsoid. Same concept, various constants.
Ellipsoid has different r along each axis (for 3D it's a, b, c when a=b=c it's sphere), in that case for every dimension there has to be a separate r.

String theory and supersymmetry theory say that our universe is 10D. After the Big Bang 3 dimensions grew bigger but other extra 7 dimensions remained tiny, hence undetectable.

I digress but here's an interesting snip:

Gravity can be properly localized to a sub-spacetime. Gravity acting in the hidden dimensions affects other non-gravitational forces such as electromagnetism. In fact, Kaluza's early work demonstrated that general relativity in five dimensions actually predicts the existence of electromagnetism. However, because of the nature of Calabi–Yau manifolds, no new forces appear from the small dimensions, but their shape has a profound effect on how the forces between the strings appear in our four-dimensional universe. In principle, therefore, it is possible to deduce the nature of those extra dimensions by requiring consistency with the standard model, but this is not yet a practical possibility. It is also possible to extract information regarding the hidden dimensions by precision tests of gravity, but so far these have only put upper limitations on the size of such hidden dimensions.
In a nutshell: we are stuck in 3D space (there are other dimensions tho), but gravity can "leak" into other dimensions, and even from there it can affect our world. And our world with all its interactions also depends on the shape of those tiny dimensions. Some scientists think that extra dimensions got something to do with dark matter and energy. And maybe it's even possible to create a "shortcut" (wormholes) through the extra dimensions to our world, in that case we could travel with infinite speed and immediatley appear in any desirable spatial and maybe even time destination.

Wow my post is huge

#### AlienIsGOD

I'm not even sure if a human could walk around the earth in a lifetime.

#### horik

I think infinity is impossible so getting a right answer about question related with it is impossible.The question is stupid,if you try to answer you are accepting that there can be more infinities in the space of 1. This is like asking:if a ship flies at an infinite speed,another ship flying at double that speed would be faster?I go to sleep e_e

#### Benetanegia

##### New Member
Ellipsoid has different r along each axis (for 3D it's a, b, c when a=b=c it's sphere), in that case for every dimension there has to be a separate r.
Yeah I know that. As I said, same concept but different constants. I went with an sphere to make explaining the concept easier and I guess I didn't explain myself properly anyway. Well, mentioning the sphere, I was just trying to explain the concept of "living in a surface", you know, to draw a parallelism between g (on Earth's surface) and c on our apparent universe. Speed of light could be any value, even infinite in the broader universe, and our apparent universe might just be that one (subset) in which c=300000 km/s.

String theory and supersymmetry theory say that our universe is 10D. After the Big Bang 3 dimensions grew bigger but other extra 7 dimensions remained tiny, hence undetectable.
Yeah, and isn't there one that says there's 23? What I think is that we don't really know how many dimensions are there in the universe. And whenever we find out exactly how many are there in "our universe", if we happen to live in a "subset" of a broader universe we might never find out how many are there on top of the ones that define our universe.

For example a living being that belongs to a universe with only 2 spatial dimensions would be able to sense or explain a 3rd dimension? Since his universe is just as "defined" by the lack of a 3rd dimension as he is, would he even theoritize about it's existence?

#### trickson

##### OH, I have such a headache
infinity is an abstract concept and does not exist in the physical universe, so linking infinity and physical things leads to paradoxes because the underlying assumption is wrong (that something physical an be infinite)

it doesn't stop you from doing math with it of course
I disagree , There are an infinite number of assholes on this planet .

#### Yukikaze

I disagree , There are an infinite number of assholes on this planet .
That number is actually easily bounded, thus not infinite

#### trickson

##### OH, I have such a headache
that number is actually easily bounded, thus not infinite :d
LOL that is funny .

#### Drone

Yeah, and isn't there one that says there's 23? What I think is that we don't really know how many dimensions are there in the universe. And whenever we find out exactly how many are there in "our universe", if we happen to live in a "subset" of a broader universe we might never find out how many are there on top of the ones that define our universe.
26 to be exact but that's for bosonic string. And only 10 for the superstring (particles + interactions, aka our regular universe which modelled as vibrations of tiny supersymmetric strings).

For example a living being that belongs to a universe with only 2 spatial dimensions would be able to sense or explain a 3rd dimension? Since his universe is just as "defined" by the lack of a 3rd dimension as he is, would he even theoritize about it's existence?
Theorizing is always possible because knowledge science intuition and imagination ain't limited. Let's take simplex. 4D simplex is a pentachoron. Even it's hard to imagine but it can easily be formulated through the geometry. Well mathematically everything is always easier than visually.

#### Benetanegia

##### New Member
Theorizing is always possible because knowledge science intuition and imagination ain't limited. Let's take simplex. 4D simplex is a pentachoron. Even it's hard to imagine but it can easily be formulated through the geometry. Well mathematically everything is always easier than visually.
Ok yes, it could be theorized to an extent, but it wouldn't form part of science, even if someone could come up with something crazy, because it wouldn't be able to be proven or falsified. That's what I meant. For example, if "speed of light" (in the broad sense, the maximum speed that a non massive particle can achieve) is actually a dimension, or something affected by one dimension, and that just happens to be constant through our universe (maybe because that's in fact the trait that sets appart our universe from others). How could we prove it? c would still be constant in our universe, and if we have no means to "trascend" our universe I don't see how could we theorize something like that. If only c is affected by that dimension (or is the dimension itself) and it's constant for us, that's the end of it.

#### Drone

Ok yes, it could be theorized to an extent, but it wouldn't form part of science, even if someone could come up with something crazy, because it wouldn't be able to be proven or falsified. That's what I meant.
That's why scientists work on Grand Unified Theory. We can't even explain mass, we can't explain gravity. We can't find Higgs or graviton. We can't say will proton decay or not. Many things ain't proven it doesn't mean we have to chuck Standard Model or relativity. It all can be explained sooner or later. For that they just need to work in different directions such as supersymmetry, quantum mechanics, string theory and so on. And finally find something general which could be integrated into TOE (theory of everything). Extra dimensions, dark matter and dark energy shouldn't scare us off.

#### AphexDreamer

That's why scientists work on Grand Unified Theory. We can't even explain mass, we can't explain gravity. We can't find Higgs or graviton. We can't say will proton decay or not. Many things ain't proven it doesn't mean we have to chuck Standard Model or relativity. It all can be explained sooner or later. For that they just need to work in different directions such as supersymmetry, quantum mechanics, string theory and so on. And finally find something general which could be integrated into TOE (theory of everything). Extra dimensions, dark matter and dark energy shouldn't scare us off.
Btw we've just recently found evidence for the Higgs Boson

http://www.dailymail.co.uk/sciencet...on-First-hard-evidence-God-particle-CERN.html

#### NinkobEi

inifnity / 0 = mind blown

#### MilkyWay

Infinity goes on for ever so you can never fill up infinity. If new guests arrive then they would all have to move up rooms and those rooms would be filled up in an endless cycle because you could never fill them up. All those rooms all instantly exist at the same time.

At the same time every infinite room is already taken up so there can be no more room, which is why its a paradox.

#### qubit

##### Overclocked quantum bit
I see that people's brains are hurting nicely here. Don't worry my friends, the finest minds in science couldn't fully get it either and more than one went nuts trying...

Now, just try getting your heads around infinitesimals: teeny tiny non-zero values infinitely close to zero that you can never measure...

#### AphexDreamer

Or trying warping your head around the fact that there is no such thing as the present, only the immediate past and imminent future.
http://en.wikipedia.org/wiki/Present

Although I must point out early the grammatical meaning of the word does exist.

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#### Drone

Or trying warping your head around the fact that there is no such thing as the present, only the immediate past and imminent future.
Yes because space-time is descrete (Planck time 10^-44 s and Planck length 10^-35 m as building blocks). Quantum mechanics might suggest that space-time is a quantum and not continuum thing. We know that space-time can be affected by gravity so maybe space-time is made of quantums and has a mass.