Can Light Ever Stand Still in the Universe?

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Discussion Overview

The discussion revolves around the concept of a light horizon in the context of the universe's accelerating expansion. Participants explore whether there exists a region where light is unaffected by this acceleration and cannot reach observers, as well as the implications of such a horizon on the behavior of light in the universe.

Discussion Character

  • Exploratory
  • Debate/contested

Main Points Raised

  • Some participants inquire about the existence of a light horizon that would act as a "no man's land" where light is not affected by the universe's acceleration.
  • One participant suggests that while light emitted from beyond the cosmological horizon cannot reach us, light is still influenced by the universe's accelerating expansion even beyond this horizon.
  • A participant points out that there is no region in the universe where light can "stand still" relative to the expansion.
  • There is a reference to a resource by Brian Powell regarding cosmological horizons, although access to this resource is problematic for some participants.

Areas of Agreement / Disagreement

Participants express differing views on the nature of light horizons and their relationship to the universe's expansion. There is no consensus on the existence of a region where light is unaffected by acceleration, and the discussion remains unresolved.

Contextual Notes

Some participants note issues with terminology and access to external resources, which may affect the clarity of the discussion. The implications of cosmological horizons and their definitions remain a point of contention.

wolram
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Is there such a thing as a light horizon where light is not effected by acceleration of the universe, and light can not reach us? a sort of no mans land.

EDIT.
 
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Thanks Jorie but that site will not show for me
 
wolram said:
Is there such a thing as a light horizon where light is not effected by acceleration of the universe, and light can not reach us?

The cosmological horizon satisfies the second part of this (light emitted by objects beyond our cosmological horizon cannot reach us), but not the first (light, and everything else, is still affected by accelerating expansion beyond the cosmological horizon).

As far as the title of this thread, there is no place where light "stands still" with respect to the expansion of the universe.
 
wolram said:
Thanks Jorie but that site will not show for me

Click "Insights" and search for "cosmological horizons".
 

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