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An example of the "second" dimension is the shadow of a three-dimensional object. How do we describe the "first" dimension? What would be an example of matter in the first dimension? There is a fundamental misunderstanding in your question: matter can exist only in three dimentions. When we talk of fewer dimensions we are making an abstract, ...

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You say: The "third" dimension is the one we experience day-to-day but this is not so. We experience three (spatial) dimensions, but there is no distinction between the first, second and third dimensions. For example I might choose the first, $x$, and second, $y$, dimensions to be horizontal and the third $z$, dimension to be vertical. I live in the ...

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To explicate what we mean by no significance, I would suggest that you understand the indexing as a convenient type of naming. We need some way to say which dimension we are referring to and using numbers lets us use convenient notation, but we could just as well have named the dimensions. The ones we experinece might be Tim, Alice, Bob, and Carol. Any new ...

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Of course there are forward and backward. Now reduce the number of dimensions to just one, leaving just a magnitude Note that it is a magnitude, not an absolute magnitude. a direction paramaterized by two discrete symbols +,- has been added. No. There is only one value there which is a member of $\mathbb{R}$. The sign is part of the value. ...

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You're confusing the definition of a vector. A vector always has magnitude and orientation regardless of the dimensionality and they are not independent. In typical physics applications, the magnitude is the Euclidean norm of the vector. So in 3D, you have 3 components defined by scalars multiplied by the unit, or basis, vectors. In 2D, you have 2 ...

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There is no significance to the numbering of the dimensions. When we refer to a vector it's common to write is as $x^\alpha$, where $\alpha$ runs from zero to the number of spacetime dimensions minus one. $x^0$ is frequently used to refer to the timelike dimension, so $x^1$ to $x^n$ refer to the $n$ spatial dimensions. However there is no signficance as to ...

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I think that many different dimensions and metric signatures have their specific “privileges”. More general, different geometries in a broader sense, and, even more general, different underlying mathematical structures (such as fields other than ℝ) also could be models for space-time of some alternative physics. But is was just (necessary for me) ...

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The answer is more simple than you think. Time is that, which is measured by (technologically suitable) clocks. Physical theories will simply tell you how clocks behave under certain conditions. This is purely descriptive. There is not a single physical theory out there, that gives a microscopic description of time, although the similarity of time with ...

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Okay, I am going to try and give this a shot, but this is most probably not going to be a decisive answer. Let us operate with the term event time and duration and consider only special relativity (SR). The conclusions of general relativity should be the same for reasonable space-times. (e.g. without closed time-like curves etc.) We expect event time to ...

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Duration is certainly a more physical concept than time. Duration is something you may measure between timelike separated events while time is always something you compute by adding up duration measurements + an arbitrary constant to fix the origin. Duration is experimental and relational while time (e.g. GPS time) is an abstract a posteriori ...

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Where a string carves out a $2$-dimensional world-sheet and a point particle carves out a $1$-dimensional world-line of spacetime, the instanton carves out a $0$-dimensional world-point. Counting only spatial dimensions, a string is $1$-dimensional and a point particle is $0$-dimensional. By logical extension, an instanton has dimension $-1$, if we only ...

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The FRW spacetime can be written as ${\bf R} \times {\bf \Sigma}$ where ${\bf R}$ where ${\bf R}$ represents the time direction and ${\bf \Sigma}$ is a homogeneous and isotropic three-manifold representing the spatial dimensions. This means that for every time there is a corresponding hypersurface for space. To help with the visualisation of hypersurfaces ...

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yes .we can see the fourth dimension of 4d objects with a third eye.And we can only see the 4th dimensions of objects that are 4d with third eye. but unfortunately we , humans are 3d objects who can see maximum up to the 3 rd dimension of our world which is in a 4d universe!

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In some extra-dimensional models, such as brane cosmology, the fields (except gravity) are indeed confined to a lower-dimensional surface, which is sort of like "sharing almost the same coordinates in the extra dimensions". In Kaluza-Klein theory with compact extra dimensions, the fields are basically spread evenly across the entire size of the extra ...

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They are just saying that in our universe of 3 spatial dimensions the event horizon is a 2-sphere. Ignoring time, our universe is a 3 dimensional manifold because it takes 3 numbers to specify a point within it. Likewise, an event horison is a 2 dimensional manifold because it takes 2 numbers to specify a point within it. Judging by the comments there is ...

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Relativity treats spacetime as a four dimensional manifold equipped with a metric. We can choose any system of coordinates we want to measure out the spacetime. It's natural for us humans to choose something like $(t, x, y, z)$, but this is not the only choice. Even in special relativity the Lorentz transformations mix up the time and spatial coordinates, so ...

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If u think of time as we percieve it as a fourth dimension time is actually all space and vice versa. We can only percieve the present at any time so every moment I guess is its own dimension or universe making time a record of all the space every moment in a way. The past can never be changed and the future can't be affected until it's the present. That's ...

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Our visualization horizon is limited to our 3 dynamic dimensions. We can only observe the other dimensions effects like watching TV program which detects passing non visual waves by the antenna. The same is with quantum entanglements event. We see only the result. Therefore, if results are modulated well with good sensors, we will see from other dimensions ...

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Your diagram looks like an illustration of the Ekpyrotic universe. In this model the extra dimensions are not compactified (i.e. curled up) so there is no uncurling of them. The reason we don't see the extra dimensions is because our universe is confined to a 3D brane, not because the extra dimensions are curled up. One well known theory for what determines ...

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