Does a Flat Universe Have an Edge?

Click For Summary

Discussion Overview

The discussion centers around the concept of a flat universe and whether it possesses an edge. Participants explore the implications of a flat universe in the context of cosmology, referencing various models and interpretations of space and geometry.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant references a source suggesting that a flat universe could imply the existence of edges, comparing it to a flat piece of paper that expands.
  • Another participant proposes that a flat universe could be infinite, which might explain the absence of edges.
  • A different participant points out that the term 'flat' does not equate to flat surfaces like paper or tabletops, suggesting a need for clarification on the terminology used in cosmology.
  • Another participant agrees that 'flat' indicates the universe lacks edges that could 'curl' back, but emphasizes that this does not clarify whether the universe is infinite in extent.

Areas of Agreement / Disagreement

Participants express differing views on the implications of a flat universe, particularly regarding the existence of edges and the nature of infinity. There is no consensus on these points, and the discussion remains unresolved.

Contextual Notes

Some participants highlight the need for clearer definitions of 'flat' in cosmological terms, indicating that misunderstandings may arise from the use of everyday language to describe complex concepts.

pivoxa15
Messages
2,250
Reaction score
1
I have read from Universe by Freedman, Kaufmann that our universe is largly flat so it would mean there are edges in our universe. Our universe would be like a flat piece of paper that is continually expanding. A more realistic picture might be a diagram of einstein's fabric of space time which is a flat sheet with spheres of planets sitting on it. But from the same source they stated that the universe does not possesses an edge. I can see that a spherical universe would not possesses an edge but how does a flat thing not have an edge?
 
Astronomy news on Phys.org
pivoxa15 said:
I can see that a spherical universe would not possesses an edge but how does a flat thing not have an edge?

If it's infinite!
 
Agreed, Labguy. 'Flat' merely means the universe has no 'edges' that can 'curl' back. It has nothing to do with whether or not the universe is temporally or spatially infinite.
 

Similar threads

  • · Replies 25 ·
Replies
25
Views
4K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 54 ·
2
Replies
54
Views
6K
  • · Replies 24 ·
Replies
24
Views
5K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 17 ·
Replies
17
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K