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Astrophysics/Hubbles red shift

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Question
I was looking at some of your answers in astrophysics related question--- like Red shift. It appears to me you explain it in terms of Doppler effect. But red shift can occur  due to other two distinct processes like gravitational  red shift i.e time dilation per GR or expanding universe per Huuble's law.
Are they all same or they have their own components attributing to this toal Red shift.

Thanks in advance

Answer
Expansion of the universe (Hubble) gives us velocities for distant objects. This causes the Doppler shift, so those two are one and the same. It's the dominant contribution, but gravitational red shifts are accounted for with massive objects, in agreement with observations. That is, indeed, a recognized second contribution to red shift.

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Dr. Stephen O. Nelson

Expertise

Fusion, solar flares, cosmic rays, radiation in space, and stellar physics questions. Generally, nuclear-related astrophysics, but I can usually point you in the right direction if it's not nuclear-related or if it's nuclear but not astrophysics.

Experience

Just moved from being a physics professor at the University of Texas of the Permian Basin into government work. Doctoral dissertation was on a reaction in CNO-cycle fusion, worked in gamma-ray astronomy in the space science division of the naval research laboratory in the high-energy space environment branch.

Organizations
Government work as a physical scientist with a nuclear focus.

Education/Credentials
Ph.D. in physics, research was on nuclear fusion reactions important in stellar fusion, further work on space telescope technology.

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