Does an Expanding Universe Alter How Quickly Light Travels Through Space?

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SUMMARY

The discussion centers on the implications of an expanding universe on the speed of light. As the universe expands, space stretches, which raises the question of whether light takes longer to traverse this "new meter." The consensus is that light does indeed take longer to travel as distances increase due to the expansion of space. Additionally, the conversation touches on the consistency of time across the universe, particularly in areas devoid of mass, and its potential effects on the speed of light.

PREREQUISITES
  • Understanding of cosmology and the expanding universe concept
  • Familiarity with the principles of general relativity
  • Knowledge of the relationship between time and space
  • Basic grasp of light propagation in vacuum versus gravitational fields
NEXT STEPS
  • Research the implications of cosmic expansion on light travel time
  • Study general relativity and its effects on time dilation near massive objects
  • Explore the concept of spacetime and its relevance in cosmology
  • Investigate the behavior of light in different gravitational fields and voids of space
USEFUL FOR

Astronomers, physicists, and students of cosmology who are interested in the relationship between the expansion of the universe, light propagation, and the nature of time.

Gal
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As the universe expands, space itself gets "stretched" and objects drift apart, like dots on elastic surfaces when force is applied. So one meter billions of years ago is two meters today, but does it necessarily mean light takes twice as long to travel this "new meter"?
 
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Gal said:
As the universe expands, space itself gets "stretched" and objects drift apart, like dots on elastic surfaces when force is applied. So one meter billions of years ago is two meters today, but does it necessarily mean light takes twice as long to travel this "new meter"?
Yes.
 
Gal said:
As the universe expands, space itself gets "stretched" and objects drift apart, like dots on elastic surfaces when force is applied. So one meter billions of years ago is two meters today, but does it necessarily mean light takes twice as long to travel this "new meter"?

This is kind of similar to a question I have.
My question is: do we know that time stays consistent throughout all the universe. We know that time and space are intertwined, and that time is relative depending on mass, such as near an event horizon. Does the absence of any mass, out in the voids of space, between galaxies, also affect time's consistent? If not, would light pass though these areas at a different rate comparatively?
 

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