A Problem with (Almost) Universal Red Shift

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Discussion Overview

The discussion revolves around the concept of redshift in the context of the expanding universe, specifically questioning the implications of universal redshift and the motion of galaxies relative to Earth. Participants explore the nature of cosmic expansion and the local motion of galaxies.

Discussion Character

  • Exploratory, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant suggests that if all super massive objects are motionless and spacetime is expanding, then the observed redshift could be explained without local motion towards Earth.
  • Another participant believes that distant galaxies have random local motions, but these are negligible compared to the redshift caused by cosmic expansion.
  • A third participant notes that while some galaxies may have varying motions towards us, the average redshift increases with distance.
  • A fourth participant asserts that the observations align with the foundational principles of the expanding universe theory.

Areas of Agreement / Disagreement

Participants express differing views on the nature of galaxy motion and the interpretation of redshift, indicating that multiple competing perspectives remain without consensus.

Contextual Notes

Some assumptions about the nature of motion and redshift are not fully explored, and the discussion does not resolve the implications of local versus cosmic motion.

jaston
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It is my understanding that, except for a couple of local galaxies, everything in the universe is moving away from us as well as from each other (relationships between inhabitants of local galactic groups excepted). If my information is acurate, how is it that a large collection of randomly placed objects could possibly act in that way? Wouldn't some of them have to be moving toward us?

I ask because the only way that makes sense to me is if all super massive objects/groups in the universe are actually motionless and the spacetime between them is expanding. Any motion at all from them would, in some direction, be read as a blue shift and just by the strength of numbers, some of those blue shifts would be pointing in our direction.
 
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I believe (not really sure) that distant galaxies DO have a local motion that is random relative to their direction to earth, BUT this motion is utterly trivial relative to the "motion" we see due to expansion.
 
Sure, there are variations where some have more motion towards us than others do, but as you get further and further away the average redshift steadily increases.
 
No mystery here. This is the foundation for the expanding universe idea.
 

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