Flat Universe possess an edge?

In summary, according to Freedman and Kaufmann's book Universe, our universe is largely flat and expanding, similar to a flat sheet of paper with planets on it. However, despite this flatness, the universe does not possess any edges. This is because "flat" in this context refers to the lack of curling edges, and not to the temporal or spatial nature of the universe.
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pivoxa15
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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 Einstien'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?
 
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  • #2
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!
 
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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.
 

1. What is a "Flat Universe"?

A Flat Universe refers to the shape of the universe, which is believed to be flat based on current scientific evidence. This means that the universe has a Euclidean geometry, where parallel lines never meet and the sum of the angles of a triangle is always 180 degrees.

2. How can the universe be flat if it's constantly expanding?

The flatness of the universe does not refer to its size or expansion, but rather its overall shape. Think of it like a deflated balloon - it can still be flat even as it expands. The expansion of the universe occurs within its flat shape.

3. Does a flat universe have an edge?

This is a debated topic among scientists. Some theories suggest that the universe may have a finite size and therefore an edge, while others propose that it is infinite and has no edge. It is currently unknown and will require further research and observation to determine.

4. What is beyond the edge of a flat universe?

Since the existence of an edge in a flat universe is still uncertain, it is impossible to say what may lie beyond it. Some theories suggest that there may be other universes or dimensions beyond our own, but this is purely speculative at this point.

5. How do we know that the universe is flat?

Scientists have been able to measure the geometry of the universe through various methods, such as observing the cosmic microwave background radiation and studying the distribution of galaxies. These observations have consistently shown that the universe has a flat shape. However, as with any scientific theory, further evidence and research may lead to new understandings and revisions of this concept.

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