Naz

2016-Jun-10, 01:13 PM

Hello, my first post:

I start a course in September: An Introduction to Astrophysics and Cosmology, and I have started reading one of the course texts An Introduction to Galaxies and Cosmology by Jones,Lambourne and Serjeant. I am enjoying it but getting a bit confused by the explanation of red shift. It was described as a phenomena distinct from Doppler.

The red Shift result is simple in its outcome. It's more the explanation and the distinction between red shift and the doppler effect that I do not appreciate. The Doppler Effect is due to Relative motion between source and observer. My text book says that "Redshift is not attributable to the Doppler Effect".

I assume that all that they are getting at here is that the end result is the same, but that Doppler Shift produced by a galaxy moving through space away from us, is different in cause from a distant galaxy moving away from us because space itself is expanding. Same effect just different case?

I am a bit unsure how space itself is created, doesn't that have to be through the motion of an outer envelope of space, or matter but into what? I realise this has probably been done a thousand times.

I have also been looking at some videos by a chap called Michael van Biezen who does a lot of teaching courses for students on Youtube. he has a series on the calculating of distance and there are some videos about how the ancient Greeks calculated the circumference of the Earth, and the diameter of the Moon from really clever observations.

I think I am just going to carry on ploughing through my text book otherwise I will get easily distracted. Thank you very much for reading.

I start a course in September: An Introduction to Astrophysics and Cosmology, and I have started reading one of the course texts An Introduction to Galaxies and Cosmology by Jones,Lambourne and Serjeant. I am enjoying it but getting a bit confused by the explanation of red shift. It was described as a phenomena distinct from Doppler.

The red Shift result is simple in its outcome. It's more the explanation and the distinction between red shift and the doppler effect that I do not appreciate. The Doppler Effect is due to Relative motion between source and observer. My text book says that "Redshift is not attributable to the Doppler Effect".

I assume that all that they are getting at here is that the end result is the same, but that Doppler Shift produced by a galaxy moving through space away from us, is different in cause from a distant galaxy moving away from us because space itself is expanding. Same effect just different case?

I am a bit unsure how space itself is created, doesn't that have to be through the motion of an outer envelope of space, or matter but into what? I realise this has probably been done a thousand times.

I have also been looking at some videos by a chap called Michael van Biezen who does a lot of teaching courses for students on Youtube. he has a series on the calculating of distance and there are some videos about how the ancient Greeks calculated the circumference of the Earth, and the diameter of the Moon from really clever observations.

I think I am just going to carry on ploughing through my text book otherwise I will get easily distracted. Thank you very much for reading.