What Causes the Big Crunch and How Does it Affect the Universe's Expansion?

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Discussion Overview

The discussion revolves around the Big Crunch theory, exploring its implications for the contraction of space and the dynamics of the universe's expansion. Participants examine the relationship between dark energy, gravity, and the overall structure of the universe, questioning how these forces interact during potential contraction scenarios.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that the Big Crunch involves the contraction of space itself, while others suggest it may primarily be due to gravitational attraction between galaxies.
  • There is uncertainty about whether the universe would experience a gradual decrease in expansion leading to contraction or if galaxies would simply attract each other, resulting in a dense concentration of mass.
  • One participant questions how gravity interacts with space during contraction, pondering if gravity could cause space to contract alongside matter or if space would remain unaffected.
  • Another participant reflects on the nature of dark energy, suggesting it causes the expansion of space directly, but its role in a potential contraction scenario remains unclear.
  • Concerns are raised about the symmetry of expansion and contraction, with some arguing that if space expands, it should also contract symmetrically, while others challenge this assumption.
  • There is a discussion about the calculation of singularities in the universe and black holes, with one participant questioning the foundational concepts behind these calculations.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the mechanics of the Big Crunch, the role of dark energy, and the relationship between gravity and space. The discussion remains unresolved, with no consensus on key aspects.

Contextual Notes

Some participants acknowledge their lack of understanding of the subject, indicating that foundational concepts may be missing or unclear. The discussion also highlights the speculative nature of the theories being discussed, particularly regarding the behavior of space and gravity.

  • #31
To put it quite simply, if we assume that the Big Bang concept is correct, then space (and time) were created as a result of it. Space isn't a separate entity that simply is "out there". Space is a function of mass. Without the Big Bang, there is no space. Without mass, there is no space. Therefore, if one wants to postulate a "big crunch", it has to include the elimination of everything, mass, space, energy...everything.
 
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  • #32
Naty1 said:
note that frame dragging IS a theoretical phenomena; do not know if there is any experimental/obserbational evidence...
Hmm looks like there is some evidence for it after all.Have a look at the below link.
http://web.mit.edu/newsoffice/1997/blackholes.html"


Naty1 said:
too much speculation here...but the potential could, I guess, exist for everything to eventually end up as black holes, and over eons those smaller ones coalesce together...but as I understand things, that still doesn't collapse all space in the universe into a crunch from what is currently known...

On the other hand things/views/theories/insights change so I never say never...
i know but that it sounded good(it still does) when i first thought of it.thanks anyway
 
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  • #33
LBrandt said:
Space isn't a separate entity that simply is "out there". Space is a function of mass.

While I don't disagree with anything else you said, the above does not follow. You went from space to mass.
 
  • #34
Excellent name for a candy bar...on that I'm sure we all agree.
 
  • #35
Space without 'space' is illogical to me. I fail to see how 'quantum fluctuations' can arise in the absence of 'space'. I'm a fan, but, not a huge fan of 'creation ex nihilo'. But 'eternal space' is not a satisfactory alternative. There must be a better alternative.
 
  • #36
Sri...good find from MIT:

They showed that the matter's orbit in the accretion disk would wobble, much as a child's top wobbles when it slows down. The frequency at which it would wobble, based on their calculations, turned out to be the same frequency as the actual oscillations in intensity of the x-ray emissions previously measured by other researchers. They theorized that this wobble is evidence of frame-dragging, because the matter's orbit can only wobble if the space and time in which it exists are being dragged.

a possible verification of frame dragging?? So they think...
 
  • #37
Maybe the accretion disk is the gamma rays burst in young galaxies...
 

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