Is the Universe Finite or Infinite in Space?

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Discussion Overview

The discussion revolves around the nature of the universe's spatial extent, specifically whether it is finite or infinite. Participants explore theoretical models, implications of spatial curvature, and the observable universe, engaging in both conceptual and technical reasoning.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question what exists beyond the universe if it is finite, while others suggest that if it is infinite, it challenges humanity's ability to conceive the 'big picture'.
  • It is noted that standard cosmological models include open, flat, and closed universes, with the flat model being consistent with current observations of the cosmic microwave background, but the finiteness or infiniteness remains an open question.
  • Some argue that if the universe is finite, it is unbounded, meaning it has no edges, using the analogy of a two-dimensional being on a sphere's surface.
  • There are inquiries about whether objects that were once moving away could eventually move towards an observer, and how the rate of expansion relates to this, with references to general relativity and the speed of light.
  • Some participants introduce speculative ideas about neutrinos potentially having tachyonic properties and discuss the implications of mass and energy in relation to the speed limit set by relativity.
  • Concerns are raised about whether the calculated age of the universe reflects only detectable data, suggesting limitations in our understanding of the universe's size and expansion.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the finiteness or infiniteness of the universe, the implications of spatial curvature, and the nature of cosmic expansion. The discussion remains unresolved with no consensus reached.

Contextual Notes

Participants highlight the distinction between the universe and the observable universe, noting that the observable universe is finite due to the finite speed of light. There are also discussions about the limitations of current models and the assumptions underlying them.

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  • #32
if infinite means growing quicker than you can measure then yes infinite is possible.
if it is growing then i see (without fact) that its a spiral growth
if its finite that would mean an overlap which kinda makes it infinite..
or an finite inward spiral..
i kinda feel that there's at least 3.or 3 parts to 1
all guess work and my thoughts on the question.
 
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  • #33
lostprophets said:
if infinite means growing quicker than you can measure then yes infinite is possible.
if it is growing then i see (without fact) that its a spiral growth
if its finite that would mean an overlap which kinda makes it infinite..
or an finite inward spiral..
i kinda feel that there's at least 3.or 3 parts to 1
all guess work and my thoughts on the question.

My thoughts are more along the line of infinite 3D spirals of infinite size in either direction...if you can get your head around that!
Can someone show me how to express that mathematically??

p.s. by "3D SPIRAL" I mean a spherical spiral with the diminishing point at the centre and all other infinite spirals having the same common diminishing point
 
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  • #34
It is useful to qualify the term to avoid ambiguity, will the universe last for an infinite time or is space of infinite size at any particular time. I'll assume you are asking about the latter.

lostprophets said:
if infinite means growing quicker than you can measure then yes infinite is possible.

It does not mean that, it means that that no matter how far you travel, you will not find yourself in a region you have already traversed.

if it is growing then i see (without fact) that its a spiral growth

The expansion of the universe is a linear scaling, it grows in all directions at the same rate (currently roughly 1% per 200 million years).

if its finite that would mean an overlap which kinda makes it infinite..

It would wrap round so you start passing through regions you have already seen.
 

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