Redshift: Speed of Light & Beyond?

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SUMMARY

This discussion clarifies the concept of redshift in relation to the expansion of the universe. Galaxies farther away from Earth exhibit higher redshift values, with some moving at redshift 6, indicating speeds approaching or exceeding the speed of light due to the rapid expansion of space. It is established that galaxies beyond 14 billion light years are receding faster than light, which does not contradict Special Relativity as they are not moving through space faster than light, but rather the space itself is expanding.

PREREQUISITES
  • Understanding of redshift and its implications in cosmology
  • Familiarity with the concept of the expanding universe
  • Knowledge of Special Relativity principles
  • Basic grasp of astronomical distances and light years
NEXT STEPS
  • Research the implications of redshift in cosmology
  • Study the principles of the expanding universe and Hubble's Law
  • Learn about the observable universe and its limitations
  • Explore the effects of Special Relativity on cosmic distances
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Astronomers, astrophysicists, and students of cosmology seeking to understand the dynamics of galaxy movement and the implications of redshift in the context of the universe's expansion.

EMFsmith
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Just a little confused about amounts of redshift, I read somewhere about redshift and how some galaxies are moving at redshift 3 (I think), which was said to be at or near the speed of light, then later in the article is said a galaxy was found to be moving at redshift 6.

I understand how the universe is expanding, and its this expansion that is increasing the distance, what I don't get is how some things are moving away faster than others, Is it relevant to their distance from us or something?

So any help here would "ease my worried mind, ooooh". :smile:
 
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EMFsmith said:
Just a little confused about amounts of redshift, I read somewhere about redshift and how some galaxies are moving at redshift 3 (I think), which was said to be at or near the speed of light, then later in the article is said a galaxy was found to be moving at redshift 6.

I understand how the universe is expanding, and its this expansion that is increasing the distance, what I don't get is how some things are moving away faster than others, Is it relevant to their distance from us or something?

So any help here would "ease my worried mind, ooooh". :smile:

Galaxies that are farther away are moving away more rapidly than galaxies that are closer to us. This is because space is expanding more rapidly as the distances increase. The farther something is, the more rapid its motion away from us. In fact, if you keep looking far enough, you'll find galaxies moving near the speed of light away from us, because space is expanding that fast at those distances.

In case you do not know, anything that is beyond 14 billion light years away from us is moving away from us at GREATER than the speed of light. This means that it is beyond the observable part of our universe and we cannot see it because the light that has left those places have not reached us. This does not violate Special Relativity because the galaxy is not moving at greater than the speed of light relative to the space around it, but because the expansion of space around it is so great, it exceeds the speed of light.
 

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