Are We Also Expanding with the Universe?

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Discussion Overview

The discussion revolves around the concept of cosmic expansion and whether it affects all systems of particles, including those within galaxies and other local structures. Participants explore the implications of the universe's expansion on smaller scales, the role of various forces, and the nature of space itself.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants propose that if the universe is expanding, then all systems of particles, including those in galaxies, are also being stretched, albeit at a very small scale.
  • Others argue that expansion is primarily an intergalactic phenomenon and does not apply to local structures due to the dominance of gravitational and other forces at short distances.
  • It is suggested that while space itself is expanding, the forces acting on particles (gravity, electromagnetic, etc.) prevent them from being affected by this expansion.
  • One participant notes that small bodies do not get stretched with space, but rather the space in which they are located is what expands.
  • Another viewpoint emphasizes that dark energy is thought to drive the accelerated expansion of the universe, but questions the necessity of dark energy in explaining expansion at smaller scales.
  • There is a distinction made between intergalactic space, which is considered homogeneous, and local space, which is not, suggesting that the geometry of space influences cosmological understanding.

Areas of Agreement / Disagreement

Participants express competing views on whether local systems are affected by cosmic expansion. There is no consensus on the relationship between local forces and the expansion of space.

Contextual Notes

Limitations include the dependence on definitions of "expansion" and the unresolved nature of how local forces interact with cosmic expansion. The discussion does not resolve the implications of dark energy or the geometry of space on local versus intergalactic scales.

ggolu2
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Universe is expanding. I know that all the galaxies are getting away from each other due to the expansion. So in theory is it true that we along with every other system of particles are getting stretched with the space ( or the distance between our constituent particle is getting bigger and bigger (no matter how small the expansion is at this scale) )?
 
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Expansion is only an intergalactic phenomenon.
 
Space is expanding and there is no difference between intergalactic space and space in which we are present right. So why would you not agree on the fact that we are also 'expanding'?
 
Dark energy forces act on the universe at very large time scales and make it expand.

At short distances, gravity, electrical and other atomic forces are much stronger and they overwhelm the dark energy force.

Therefore, things far apart expand, things close together don't.
 
Gravity, Electromagnetic Forces, Strong and weak force acts among the particles and I think that space is not affected by them. These forces do not stretch or contracts space except gravity which only curves it. So I think that expansion of universe has nothing to do with these forces.
 
Oh I got it... Now what I got is that small bodies do not get stretched with space but the space in which they are located gets stretched.
 
anorlunda said:
Dark energy forces act on the universe at very large time scales and make it expand.

At short distances, gravity, electrical and other atomic forces are much stronger and they overwhelm the dark energy force.

Therefore, things far apart expand, things close together don't.
There is no "force" driving the expansion, nor is dark energy needed. Dark energy is thought to drive the recent accelerated expansion of the universe.
 
ggolu2 said:
Space is expanding and there is no difference between intergalactic space and space in which we are present right. So why would you not agree on the fact that we are also 'expanding'?
But there is a difference between intergalactic space and local space: the former is homogeneous and the latter is not. The geometry of space dictates the cosmology.
 

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