How can the universe keep on expanding if it's infinite?

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Discussion Overview

The discussion centers around the concept of the universe's expansion, particularly questioning how it can expand if it is infinite. Participants explore the implications of an infinite universe and whether it necessitates a boundary or border for the matter it contains.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that if the universe is expanding, it must have a border similar to a cube of aluminum, which has a surface area containing matter.
  • Another participant references an article that discusses the expansion of the universe, implying that there may be better explanations available, though the credibility of the source is uncertain.
  • A different participant reiterates the initial question about the universe's expansion and argues that an expanding universe does not necessarily require a border.
  • One participant introduces an analogy comparing the universe to a two-dimensional surface, suggesting that just as a bug cannot leave the surface, humans cannot exit the universe, implying that the concept of a border may not apply.

Areas of Agreement / Disagreement

Participants express differing views on whether the universe can be infinite and still expand. There is no consensus on the necessity of a border for the universe.

Contextual Notes

Some arguments depend on the definitions of "infinite" and "border," and the discussion includes unresolved implications of these concepts.

Aarav Sangar
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How can the universe keep on expanding if it's infinite? Expanding metal, like a cube of aluminium, has a surface area which forms a border for the matter contained inside. So the universe must have a border for the matter it contains.
 
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Aarav Sangar said:
How can the universe keep on expanding if it's infinite? Expanding metal, like a cube of aluminium, has a surface area which forms a border for the matter contained inside. So the universe must have a border for the matter it contains.

You could do a big of reading on what an expanding universe really means. Try starting here:

http://www.phinds.com/balloonanalogy/

The universe, whether it is finite or infinite need not have a border.
 
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It only has a border if you can get outside it. The nature of the universe is like the surface of a solid appears to a bug crawling on it. The bug can not get off the surface, so that dimension may as well not exist for it. The universe is like that for us, except that the dimension needed to get out of the universe really doesn't exist.
 
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Thread locked. The OP is no longer on PF.
 

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