Adding Extra Dimension for Calculations in Curved Spaces

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Discussion Overview

The discussion revolves around the feasibility and implications of adding an extra dimension to facilitate calculations in curved spaces, particularly in the context of embedding these spaces in higher-dimensional Euclidean volumes. Participants explore the potential benefits and drawbacks of this approach, touching on concepts from differential geometry and general relativity.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that adding a virtual dimension could simplify calculations in curved spaces by embedding them in a higher-dimensional Euclidean volume.
  • Another participant questions whether this approach is beneficial, arguing that calculations can be performed on a flat plane and that embedding does not change the geometric shape, thus offering no advantage.
  • A different viewpoint emphasizes that the purpose of differential geometry is to avoid reliance on embedding spaces, as this generally complicates the analysis.
  • Reiteration of the initial suggestion highlights that embedding is often used for visualization rather than for simplifying calculations, which typically require fewer variables and less redundancy.
  • One participant reflects on the misconception that the simplicity of Euclidean rules would outweigh the complexity introduced by an additional spatial variable.
  • A reference is made to Kip Thorne's popularizations regarding embedding approaches, alongside a mention of alternative methods in general relativity that utilize flat spacetime with warped rulers and clocks.
  • Concerns are raised about the limitations of certain approaches in modeling topological features relevant to black holes, although these limitations are not discussed in detail by the referenced author.

Areas of Agreement / Disagreement

Participants express differing views on the utility of adding an extra dimension for calculations in curved spaces. There is no consensus on whether this approach is beneficial or complicates matters, indicating an unresolved debate.

Contextual Notes

Some participants note that embedding spaces may complicate calculations rather than simplify them, and there are references to specific limitations in modeling certain features of general relativity. The discussion remains open to various interpretations and approaches.

Kairos
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as calculations are technically difficult in curved spaces, I wonder if we would obtain the same results by adding one additional (virtual) dimension in order to embed the space in a higher order Euclidean volume, just to facilitate the treatments? (for example embed a 3D hypersphere in a 4D euclidean space)
thank you in advance
 
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Does this become easier, because it is on a flat plane?

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You can calculate with spacetime as if it was flat, at least either locally or on a global scale. Since the embedding doesn't change the geometric shape, there will be no gain in doing so.
 
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The entire point of differential geometry is not to have to rely on an embedding space because it generally complicates things.
 
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Kairos said:
as calculations are technically difficult in curved spaces, I wonder if we would obtain the same results by adding one additional (virtual) dimension in order to embed the space in a higher order Euclidean volume, just to facilitate the treatments? (for example embed a 3D hypersphere in a 4D euclidean space)
thank you in advance
Embedding curved spaces in flat higher dimensionless spaces is usually done to help with visualization. But for calculations, you usually want as few variables and as little redundancy as possible.
 
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OK thanks
I supposed that the simplicity of euclidean rules would compensate the additional spatial variable. bad idea !
 
Kip Thorne has written some popularizations in "Interstellar" about the embedding approach. But I haven't seen any non-popularized treatment of General Relativity using embeddings.

So, if you're attracted to the approach and you don't mind reading popularizations (which are usually limited, even when well written), you could try "Interstellar", but for a serious, textbook study you'd want to learn the differential geometry approach.

There's at least one other approach to GR, that uses funky fields that warp rulers and clocks in a flat space-time. This is akin to Einstein's discussion of rulers on a heated marble slab as a model for non_euclidean spatial geometries. This approach has been outlined by Straumann in "Reflections on Gravity" <<link>>. I rather suspect that Straumann's approach has some limits in regards to modelling some of the topological features that the full theory handles, and that this matters in such topics as understanding black holes, but the author doesn't discusss these limitations, unfortunately.
 
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