Cosmological expansion question

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Discussion Overview

The discussion revolves around the concept of cosmological expansion and its implications for redshift observations. Participants explore whether the expansion of the universe affects only large-scale structures while leaving atomic and local scales unchanged. The conversation touches on theoretical interpretations and seeks mathematical or physical justifications for these views.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant asserts that cosmological expansion can only be observed if stars, planets, and atoms do not expand, referencing Misner, Thorne, and Wheeler's analogy of a rubber balloon.
  • Another participant questions the absence of evidence supporting the idea that universal expansion does not occur, suggesting that local expansions (like in Brooklyn) would not produce redshift under current theories.
  • There is a claim that the redshift of galaxies is due to the stretching of light waves as space expands, leading to a question about why atoms would not also be affected by this expansion.
  • A later reply proposes that the electromagnetic force and nuclear forces locally counteract the effects of cosmological expansion on atomic scales.

Areas of Agreement / Disagreement

Participants express differing views on whether atoms are affected by cosmological expansion, with some arguing they are not while others suggest that local forces prevent such expansion. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants reference various sources and articles to support their claims, but there is no consensus on the underlying mechanisms or evidence regarding the expansion of space-time and its effects on different scales.

Invinoveritas
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I am working off the premise that:

If Cosmological expansion is really occurring a redshift (as we currently observe) can only be obtained if (stars, planets, atoms) do not expand.

See Misner, Thorne and Wheeler comment:
"Only later does he realize that the atom does not expand, the meter stick does not expand, the distance between the sun and Earth does not expand. Only distances between clusters of galaxies and greater distances are subject to the expansion. No model more quickly illustrates the actual situation than a rubber balloon with pennies affixed to it, each by a drop of glue. As the balloon is inflated the pennies increase their separation one from another but not a single one of them expands!" [MTW, 1997, p.719].

I am looking for math or physics to justify this belief.

Thany you.
 
Physics news on Phys.org
http://www.lightandmatter.com/html_books/genrel/ch08/ch08.html#Section8.2

See subsection 8.2.5.
 
Last edited by a moderator:
bcrowell said:
http://www.lightandmatter.com/html_books/genrel/ch08/ch08.html#Section8.2

See subsection 8.2.5.

Thank you for the link, I read the page and it does clear up some things, but brings up another question.

1. I don't see where they give the cause or the supporting data that universal expansion is not occurring.
Brooklyn may be expanding and if so it would not produce a red shift under the current theories.

Also

Barry Parker stated and John Peacock agreed that:
The redshift of galaxies exists because their light waves are stretched as space is stretched, and therefore their wavelength is increased"

If the expansion of space-time causes light waves to belengthened, why would atoms be excluded from this expansion?

There must be something that locally overcomes this expansion if Space-Time is truly expanding.

The article basically seems to say it is not because it cant.
 
Last edited by a moderator:
There's a bunch of references listed at the end of this entry from the Usenet Physics FAQ, you could check some of those for the math.
 
Invinoveritas said:
If the expansion of space-time causes light waves to belengthened, why would atoms be excluded from this expansion?

There must be something that locally overcomes this expansion if Space-Time is truly expanding.
The "something" that locally overcomes the expansion is the electromagnetic force and the strong and weak nuclear forces.
 

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