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  1. #1 A Quick clarification on red shift of receding galaxies 
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    Am I right in saying that the red shift of receding galaxies is not because they are moving away from us, but rather because of the expansion of the space separating us? I mean, the galaxy is not moving through space away from us, only with space. So the light emitted is not initially shifted at all, but stretches out on its way over here. Is that correct?


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    Actually its a little of both. Light from the Andromeda Galaxy is blue shifted because the galaxy itself is actually moving toward us. The light from some other galaxies in our local group is redshifted because they are moving away from us as we all orbit a central point of gravity. However space-time itself is being stretched by Dark Energy and light is stretched with it.


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    Thanks, it is as I thought.

    I meant red shift only as a result of distance (movement with space), so Andromeda's blue shift is a result of its movement through space relative to us. Cool! :wink:
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  5. #4 Re: A Quick clarification on red shift of receding galaxies 
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    Quote Originally Posted by KALSTER
    Am I right in saying that the red shift of receding galaxies is not because they are moving away from us, but rather because of the expansion of the space separating us? I mean, the galaxy is not moving through space away from us, only with space. So the light emitted is not initially shifted at all, but stretches out on its way over here. Is that correct?
    Yes, thst is the BBT version.

    But I refuted that and provided a substitute with the 'Expansion of the Light Waves' (photon) by an intrinsic force.

    Check out my article in the cosmology sector on a recent page.

    Cosmo
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  6. #5 Re: A Quick clarification on red shift of receding galaxies 
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    Quote Originally Posted by Cosmo

    Yes, thst is the BBT version.

    But I refuted that and provided a substitute with the 'Expansion of the Light Waves' (photon) by an intrinsic force.

    Check out my article in the cosmology sector on a recent page.

    Cosmo
    You're such an ass, Cosmo. Kalster's simply asking a question and you have to litter yet another thread with your inane pet theories. Any opportunity to get your crap out there for all to see, not a thread shall exist without it.
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    Actually, its ok this time Q. I just needed to make sure I had it right, which is done. :wink:

    Cosmo, I did read your thread when it was still active and your problems with the big bang seems to mostly come from your misunderstanding of the balloon analogy, which is that you seem to not be sure what it is supposed to illustrate. Then you take other parts of the balloon in the analogy, which does not form part of the analogy, and bring it into your refuting argument.
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    Quote Originally Posted by Arch2008
    Actually its a little of both. Light from the Andromeda Galaxy is blue shifted because the galaxy itself is actually moving toward us. The light from some other galaxies in our local group is redshifted because they are moving away from us as we all orbit a central point of gravity. However space-time itself is being stretched by Dark Energy and light is stretched with it.
    To be clear: all the redshift associated with Hubble's observations is due to expansion of space itself. (Or well, I don't actually believe it, but that's the theory)

    Some particular celestial bodies like Andromeda also just so happen to be moving away from us in the traditional sense of motion, so their light is even more red shifted than Hubble's redshift predicts. I'm sure some are also moving toward us, so they'd be slightly less red shifted than Hubble's predictions.

    The reason the idea of space itself expanding was introduced is because a normal Doppler red shift would never conform to Hubble's observations of a linear relationship between red shift and distance. (IE. distance * Hubble's constant = amount of redshift)

    If all objects in space were physically accelerating away from us in the traditional Doppler sense, then the fact we're seeing distant objects as they *were* instead of as they *are* would complicate the mathematics too much to allow for such a simple relationship between distance and the amount of red shift we observe.
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    G'day from the land of ozzzzz

    The BBT requires that space/time be expanding even though the observations do not show it. So they came up with an ad hoc idea to make it work, lets assume that space/time is expanding even though we do not see it.

    Observations take priority over theory based on ad hoc ideas.

    Look at as many observations and you will see it in plain light.
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    Harry, the fact that the red shifts correspond to distance is the observation of expansion. Do you have another explanation? Here comes tired light etc. with no evidence to support it.
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    G'day Kalster

    Take a bit of time to understand what expansion means.

    Than try to do a bit of research into redshift. Try to find the error in why everything is expanding from earth or is it.

    If you are happy in what you know, so be it.

    Right now I'm off to a party, doing a bit of expansion my way.
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    Quote Originally Posted by kojax
    Quote Originally Posted by Arch2008
    Actually its a little of both. Light from the Andromeda Galaxy is blue shifted because the galaxy itself is actually moving toward us. The light from some other galaxies in our local group is redshifted because they are moving away from us as we all orbit a central point of gravity. However space-time itself is being stretched by Dark Energy and light is stretched with it.
    To be clear: all the redshift associated with Hubble's observations is due to expansion of space itself. (Or well, I don't actually believe it, but that's the theory)

    Some particular celestial bodies like Andromeda also just so happen to be moving away from us in the traditional sense of motion, so their light is even more red shifted than Hubble's redshift predicts. I'm sure some are also moving toward us, so they'd be slightly less red shifted than Hubble's predictions.

    The reason the idea of space itself expanding was introduced is because a normal Doppler red shift would never conform to Hubble's observations of a linear relationship between red shift and distance. (IE. distance * Hubble's constant = amount of redshift)

    If all objects in space were physically accelerating away from us in the traditional Doppler sense, then the fact we're seeing distant objects as they *were* instead of as they *are* would complicate the mathematics too much to allow for such a simple relationship between distance and the amount of red shift we observe.
    I know that Andromeda is a member of the Local Group of galaxies. I could be wrong but I think it is moving towards the Galaxy (Milky Way). Therefore its light is not red-shifted.
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    G'day from the land of ozzzzzzz

    The centre of our local group of galaxies is M87.

    Maybe this link may give you some idea of where we are and the complexity of part of the observable universe. You can zoom in and out.

    Andromeda is at the moment moving in our direction as per main stream. But! in my opinion (non -standard) it will divert its direction because it is gravity bound by M87 and the Virgo cluster of galaxies.

    http://www.atlasoftheuniverse.com/sattelit.html

    Looking at our Milky Way from 500,000 light years we see the sattelite dwarf galaxies around the MW.

    Looking at 5 million light years we see part of the local group of galaxies with the MW.

    Looking at 500 Million light years we see our local group with other clusters of galaxies.
    In this image our local group is moving towards the Virgo Cluster.

    Looking at 1billion light years we see only super cluster of clusters of galaxies

    At 14 billion light years we see the interconnection between all galaxies.
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    Harry,
    I am sure I have asked you before, but now I am telling you - when you post something that is not mainstream please identify it as such.

    I am unaware of any predictions that Andromeda is going to be diverted from a collision with our galaxy. That may be ignorance on my part, but I think not. Therefore, either provide the peer reviewed article(s) that discuss this possibility, or indicate clearly that it is a non-standard idea.

    No one has a right to post on this forum. You have been consistently given a great deal of latitude to freely post your unconventional ideas on cosmology. You have been allowed to do this even though it violates the posting guidelines - i.e. you should not keep raising your unconventional ideas in every thread, thereby deviating that thread from its original focus.

    All I am asking you to do, in return, is to clearly identify when you are deviating from 'accepted wisdom'.

    Thank you.
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  15. #14 Re: A Quick clarification on red shift of receding galaxies 
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    Quote Originally Posted by KALSTER
    Am I right in saying that the red shift of receding galaxies is not because they are moving away from us, but rather because of the expansion of the space separating us? I mean, the galaxy is not moving through space away from us, only with space. So the light emitted is not initially shifted at all, but stretches out on its way over here. Is that correct?
    Yes, it is the space (nothing) that is expanding the light waves.

    Cosmo
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    Quote Originally Posted by Harry Costas
    http://www.atlasoftheuniverse.com/sattelit.html

    Looking at our Milky Way from 500,000 light years we see the sattelite dwarf galaxies around the MW.

    Looking at 5 million light years we see part of the local group of galaxies with the MW.

    Looking at 500 Million light years we see our local group with other clusters of galaxies.
    In this image our local group is moving towards the Virgo Cluster.

    Looking at 1billion light years we see only super cluster of clusters of galaxies

    At 14 billion light years we see the interconnection between all galaxies.
    i only want to say thank you for this link. i could keep clicking around there for days without food, beer or water.

    cheers 8)
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    G'day from the land of ozzzzzzzz

    Ophiolite said:

    I am unaware of any predictions that Andromeda is going to be diverted from a collision with our galaxy. That may be ignorance on my part, but I think not. Therefore, either provide the peer reviewed article(s) that discuss this possibility, or indicate clearly that it is a non-standard idea.
    In the statement you are correct in what you say.

    What I have stated is non-standard and I have gone back and corrected it.

    Still the logic is there. One would expect main stream to pick up the probabilty of Andromeda and the Milky Way bound by gravity to M87 and moving towards Virgo cluster.

    The only thing that is not main stream in my opinion is that they will not collide.
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    Am I also correct in saying that gravitationally bound galaxies, as in clusters and super clusters, do not register red shifts due to expansion between constituent galaxies? So then red shifts due to expansion can only occur between two galaxies that are not part of the same cluster or super cluster? And does the expansion affect the rotation around common centres of gravity at all? If so, to what degree and could this add to the rotation speed anomalies generally attributed to dark matter?


    P.S. Harry, don’t patronize me!
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  19. #18  
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    Quote Originally Posted by KALSTER
    Harry, the fact that the red shifts correspond to distance is the observation of expansion. Do you have another explanation? Here comes tired light etc. with no evidence to support it.
    Well, there's no evidence to support either view.

    Hubble observed a redshift that increased relative to the distance between us and the object observed. End of story.

    Assuming expansion or non-expansion on that basis is pure speculation. Yes, expansion of space itself could explain it, just as a serrated knife could be used to skin a cat. You could also use really sharp scissors, a variety of machines, or a non-serrated knife to skin the same cat.

    We could just as easily imagine an invisible, omnipresent force like Dark Energy is sapping the energy out of the light as imagine that space itself is expanding in a way that requires Dark Energy to maintain it.
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  20. #19 Re: A Quick clarification on red shift of receding galaxies 
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    Quote Originally Posted by KALSTER
    Am I right in saying that the red shift of receding galaxies is not because they are moving away from us, but rather because of the expansion of the space separating us? I mean, the galaxy is not moving through space away from us, only with space. So the light emitted is not initially shifted at all, but stretches out on its way over here. Is that correct?
    A model illustrating expansion. You have a solid ball a 3 inches across. Around that is a balloon a foot across. It has some spots on it (galaxies). You then impale the galaxies with 5 feet long knitting needles (which for convenience sake does not burst the balloon), which stick into the central ball (it's only reason for being there is for holding the needles in place in this model).

    The balloon now expands to 3 feet across. The knitting needles are still impaling the galaxies but the galaxies have separated. They have not moved but there is more space between them. Now the balloon is six feet across and the galaxies have still not moved because are all still impaled by the knitting needles, but there is even more space between them now.

    The balloon is a four physical dimension hypersphere. The skin of the balloon is our 3D universe. Everything is moving away from everything else but not from any central starting point (that we 3D people can detect).

    Photons cannot stretch. The idea is that every second, the thing we are looking at is moving further away from us (as distance increases by expansion of space between us). That would be like the receding sound of a train whistle, except that light does not behave like sound.
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    Quote Originally Posted by KALSTER
    Am I also correct in saying that gravitationally bound galaxies, as in clusters and super clusters, do not register red shifts due to expansion between constituent galaxies?

    The idea is that "local gravity" in a cluster (or even in a galaxy) is sufficient to overcome expansion so everything does not drift apart.

    The Hubble Constant (expansion) is about 15 miles per second over a million light years, so over the distance between us and Andromeda galaxy, space expands by 30 miles per second. But local gravity is sufficient to overcome this so not only do they not drift apart and are held together, but the gravity is sufficient to pull the Andromeda galaxy towards us (and visa versa). If not for expansion, the two galaxies would be moving towards each other at their present speed plus 30 mps increase in speed.
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    Photons cannot stretch.
    Yes they can. A single photon still has a wavelength that can be stretched by expanding space. Both light emitted from a source moving away through space and one receding with space (due to expansion) give red shifts, but for different reasons and, as I have it, they can be distinguished from each other.

    That model does not work, since we would be on the surface of the balloon too. There is no place in the big bang universe that corresponds to the ball in your analogy.
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    Quote Originally Posted by KALSTER
    Photons cannot stretch.
    Yes they can. A single photon still has a wavelength that can be stretched by expanding space. Both light emitted from a source moving away through space and one receding with space (due to expansion) give red shifts, but for different reasons and, as I have it, they can be distinguished from each other.
    Light travels at an exact speed. If space expands the width of a proton in the second it takes for light to travel 186,282 miles, it does not matter. Light will only travel the same distance and not a proton's width further. This means it takes each photon longer to reach it's target. Overall photons appear to have redshifted like frames of a movie watched all together appear to show moving images. No single photon has stretched.


    That model does not work, since we would be on the surface of the balloon too. There is no place in the big bang universe that corresponds to the ball in your analogy.

    Not on the surface of the balloon but part of the skin of the balloon. In four physical dimensions, the 3D surface would look the same to a 4D being as a sheet of paper would look to us. Flat.

    As it was just an analogy to explain expanding space, the ball exists solely to hold the metal needles in place. Think of no ball and the needles held there magically if that helps.
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    Quote Originally Posted by Cyberia
    Quote Originally Posted by KALSTER
    Photons cannot stretch.
    Yes they can. A single photon still has a wavelength that can be stretched by expanding space. Both light emitted from a source moving away through space and one receding with space (due to expansion) give red shifts, but for different reasons and, as I have it, they can be distinguished from each other.
    Light travels at an exact speed. If space expands the width of a proton in the second it takes for light to travel 186,282 miles, it does not matter. Light will only travel the same distance and not a proton's width further. This means it takes each photon longer to reach it's target. Overall photons appear to have redshifted like frames of a movie watched all together appear to show moving images. No single photon has stretched.
    That would be true if you ignored the wave nature of light. Light can also be treated as a wave. And as a wave, expanding space means expanding wavelength.
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    Light travels at an exact speed. If space expands the width of a proton in the second it takes for light to travel 186,282 miles, it does not matter. Light will only travel the same distance and not a proton's width further. This means it takes each photon longer to reach it's target. Overall photons appear to have redshifted like frames of a movie watched all together appear to show moving images. No single photon has stretched.
    As Numsgil said, light is a wave too. As a simple analogy; imagine a large pond. You throw a stone in the middle and watch the ripples go outwards. Let's say that the ripples do not dissipate. If you were to be able to magically enlarge the pond while the wave is travelling, that ripple will change to a longer and longer wavelength as it travels towards the edge. The same happens to the photons.

    Not on the surface of the balloon but part of the skin of the balloon. In four physical dimensions, the 3D surface would look the same to a 4D being as a sheet of paper would look to us. Flat.
    The forth dimension is time, which is a temporal dimension, not a physical one. The balloon analogy is one of a 2-sphere. It works, because it illustrates how expansion works in our big bang universe and how we would move in it. Our counterparts in the 2-sphere analogy are the flatlanders. They see only two dimensions. If they start at a dot, they can move to another and another until they end up back where they started, thinking that they have been travelling in a straight line. From there perspective, when the balloon inflates, the galaxies will be receding faster away from them the farther it is. Light originating from other galaxies would be redshifted (see my first point). Now, in reality we live in a 3-manifold space according to the big bang theory. We, also, would travel outward and end up back where we started, thinking we were going in a straight line. Inflation of this 3-manifold would also have the effect that the further a galaxy is, the faster it recedes. We don't need a forth spatial dimension for this setup to work. Time is a measure of relative movement and is irrevocably connected in this way to form space-time with 4 dimensions. When doing the maths, there is no difference between working with 3 space and one time dimension vs. four space dimensions, as both use the same 4-manifold maths.

    Anyway, this is how I understand it and I would love one of the big guns (Janus, Mitchell, Dishmaster, Guitarist, etc) to correct any mistakes I might have made.
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    Why is the problem not as straightforward as it appears.

    Does the increasing red-shift not simply mean that the early universe was expanding relatively faster than it is now, and as we look further out from the centre of our sphere, we naturaly see everything moving away from us at a greater rate the farther back we look, because at that earlier time everything simply was moving apart faster (relatively).

    The continuum was expanding faster in the past, and we can only observe this earlier period of faster expansion as a remote spherical shell.
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    Quote Originally Posted by ini
    Why is the problem not as straightforward as it appears.

    Does the increasing red-shift not simply mean that the early universe was expanding relatively faster than it is now, and as we look further out from the centre of our sphere, we naturaly see everything moving away from us at a greater rate the farther back we look, because at that earlier time everything simply was moving apart faster (relatively).

    The continuum was expanding faster in the past, and we can only observe this earlier period of faster expansion as a remote spherical shell.
    The current big bang model does include a period of very fast inflation. The thing is that light does not shift red from stars moving away due to expansion at the source like it would do with standard movement. It is because those galaxies are moving with space as opposed to moving through space. The only way that light can redshift as it does is if the space the light was travelling through was constantly expanding and stretching out the wavelength. The big bang should not be thought of as a standard explosion.
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