# Redshift question

**URL:** https://boards.straightdope.com/t/redshift-question/233504
**Category:** Factual Questions
**Created:** [March 10, 2004, 4:22pm UTC](https://boards.straightdope.com/t/redshift-question/233504 "2004-03-10T16:22:11Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)
#### Post date: [March 10, 2004, 4:22pm UTC](https://boards.straightdope.com/t/redshift-question/233504/1 "2004-03-10T16:22:11Z")

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In another thread it was stated how the very edge of the universe is receding away from us at speeds approaching the speed of light: this would not violate relativity because it is space itself is moving at c.

ANYWAYS…

A receding light emitter has its radaiation red shifted, so what about an emitter whithin an area of space which is itself receding? does it red shift the same way?

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### Author: ![Angua](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@Angua](https://boards.straightdope.com/u/Angua)
#### Post date: [March 10, 2004, 4:40pm UTC](https://boards.straightdope.com/t/redshift-question/233504/2 "2004-03-10T16:40:56Z")

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> [@Enola Straight](#):
>
> A receding light emitter has its radaiation red shifted, so what about an emitter whithin an area of space which is itself receding? does it red shift the same way?

How do you mean? That the transmitter is embedded in a portion of space that is receeding away from us?

If so, then yes, the radiation will be redshifted. Its a slightly different principle to that of a moving transmitter, but the overall effect is the same.

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### Author: ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)
#### Post date: [March 10, 2004, 5:02pm UTC](https://boards.straightdope.com/t/redshift-question/233504/3 "2004-03-10T17:02:36Z")

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Redshift (or blueshift) just depends on the relative velocity of the object. Regardless of the _cause_ of the motion or its environment, if it’s moving away from us, there will be redshift.
