So, what is the right question to ask about this topic?

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Discussion Overview

The discussion revolves around the nature of universal expansion, particularly the apparent contradiction between the increasing rate of expansion observed in the distant past and the gravitational attraction observed in local galactic clusters. Participants explore whether the rate of expansion can reverse and the implications of gravitational effects on local versus universal scales.

Discussion Character

  • Debate/contested
  • Exploratory
  • Conceptual clarification

Main Points Raised

  • Some participants note that while the universe is generally expanding, local gravitational effects can create regions where this expansion is not observed, leading to a complex interplay between expansion and gravitational attraction.
  • One participant suggests that the distant past featured a period of hyperinflation, which may have influenced the clumping of galaxies.
  • Another participant questions the validity of the "standard candle" explanation for the accelerating expansion of the universe, citing flawed assumptions in cosmological models.
  • There is a discussion about the nature of dark energy and its role in the dynamics of space between galaxies compared to the space between stars, raising questions about the distribution of dark matter.
  • One participant emphasizes the importance of asking the right questions in scientific inquiry, suggesting that this approach may lead to more fruitful discoveries than simply seeking answers.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between local gravitational effects and universal expansion. While some agree on the general principle of expansion, there is no consensus on the implications of this for understanding cosmic dynamics or the validity of certain cosmological models.

Contextual Notes

Participants highlight the complexity of cosmological models and the potential for unstated assumptions to influence conclusions. There is an acknowledgment of the limitations of current experimental data in cosmology.

Tyger
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If we look in the distant past we see evidence that the rate of universal expansion is increasing. If we look in the recent past we see that our own galactic cluster and many around it, including the huge Coma cluster, are headed toward a "great attractor". These are definitely opposing scenarios.

Does the rate of expansion reverse at times?
 
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yes.

not all of the galaxies we observe our red shifed. local regions will clump together, but then continue to expand. the distanct past was going through a period of hyperinflation, so there was no time to have the galaxies clump together.
 
Generally the Universe is expanding, but locally it might seem different because of the gravitation.
 
There is "small-scale" (and I use that term very loosely) non-expansion if there is enough gravitational effect in a particular region (like in a galaxy or a galaxy cluster), but the overall universe is expanding.
 
I have read that anti-gravity [or whatever dark energy is] dominates in the regions between galaxies. Is the nature of deep inter-galactic space fundamentally different than the space in between stars? Is this related to the distribution of dark matter?
 
Originally posted by Tyger
If we look in the distant past we see evidence that the rate of universal expansion is increasing. If we look in the recent past we see that our own galactic cluster and many around it, including the huge Coma cluster, are headed toward a "great attractor". These are definitely opposing scenarios.

Does the rate of expansion reverse at times?

Firstly, they are not opposing scenarios. You're confusing the issue here - space itself is expanding. Within that expansion mass can experience velocity and mass. So in the scenario you describe, there is simply the motion of mass within expanding space.

However, to that I should also point out that I am still very much against the "standard candle" explanation of the expansion of the universe acceleratnig. :) There are too many easily flawed assumptions involved to take the idea seriously. Unfortunately, it has fast become a paradigm in its own right. :(
 


Originally posted by I, Brian
Firstly, they are not opposing scenarios. You're confusing the issue here - space itself is expanding. Within that expansion mass can experience velocity and mass. So in the scenario you describe, there is simply the motion of mass within expanding space.

However, to that I should also point out that I am still very much against the "standard candle" explanation of the expansion of the universe acceleratnig. :) There are too many easily flawed assumptions involved to take the idea seriously. Unfortunately, it has fast become a paradigm in its own right. :(

First, welcome to the board and thanks for your input.

I know about "space is expanding" and the dynamics of gravity and the universal expansion, I'm just trying to get people to ask a few questions as opposed to accepting "ober dictum". And yes, I agree that there are too many assumptions used to justify too many conclusions, especially in Cosmology where expermental data is thin and hard to come by. People don't always recognize that any hypothesis carries many often unstated assumptions.

I believe the road to discovery lies in asking the right question. There are usually far fewer right questions than right answers, so looking for the right answer is like looking for a needle in a haystack. But if you ask the right question the right answers will come thick and fast.
 

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