Question 5. Why galaxy light does red shift ( wave length goes longer )?

There are three popular reasons and one reason which nobody cares.
( 1) Doppler effect by backward speed.
( 2 ) Lower Temperature. ( Temperature of space became lower because universal space expanded. )
( 3) Light expanded and wave length became longer because universal space expanded.
( 4) Red shift between stars. ( Nobody cares about this reason. )

( 1 ) is the most popular opinion among general opinions. Because ( 1 ) is the evidence of big bang. But ( 2 ) and ( 3 ) are both happened because of big bang. ( Some books say that ( 1 ) and ( 2 ) are same things. ) ( 4) is not concerned in big bang. And this is not accepted by anyone. Don't you wonder which opinion is correct and every opinion is only hypothesis or not ? But it is surely said that red shift is discovered by Hubble. But he only expressed his opinion on the relation between red shift and galaxy distance, and he suggested that we had better be careful about the opinion that the reason why is backward speed.
Consideration
( 2 ) Temperature of space became lower because space expanded.
When space expands as ordinary matter does, they say the temperature becomes lower. I wonder what is the theory of it. Can the theory be explained?
( Why the temperature of ordinary matter becomes lower according to expansion? There must be some reason. Oh! Don't blame me because I don't know it ! ) And why temperature of light goes lower when temperature of space goes lower? I've never heard that temperature of light which came from the sun with high temperature becomes lower ( wave length becomes longer ) when it arrives at south pole. Is there such phenomenon? Oh, there are so many things which I'm not sure.

( 3 ) About the opinion that light becomes bigger because space becomes wider, so light wave goes bigger and longer, then red shift happens:
According to big bang universal theory, matter wasn't flown away by big bang, but space was made then and it expanded rapidly. They say, space kept going wider since then and universe became as big as present size. So, they say that light also became bigger with the expansion of space. Little light wave might have become huge one because it expanded. If their opinion is right, a star and another star don't need to go separate to have red shift. When the space between stars expands, light can have red shift. This red shift is not concerned in Doppler effect by backward speed. Of course this could be the evidence of expansion of space. But I really wonder, is there any proof that light also expands when space expands? I wonder if they add red shift by backward speed and red shift by expansion when they calculate Hubble's fixed number. When ( 3 ) happens, ( 1 ) also happens, so I think they must be added. Especially, cosmic background radiation might have caused by ( 3 ).
By the way, space means not only the place where nothing exists but also the place where there is light. Even if there is gas there, it is space. There is liquid there, it is space. Of course even if there is solid there, we call it space. Even if there are stars there, it is space. Inside of the earth is of course a part of space. So if light expands when space expands, not only light but also gas, liquid, solid, stars, the earth, could expand. Don't you think so, too? But by some reason, they say it can't happen. Only light expands, they say.
Some people say that space is curved by gravity or they say that place where matter exists doesn't expand because gravity is bigger than the power of expansion of space. But I think they are too selfish.At first, when universe began, it was much more crammed with matter than black hole , but they say matter expands without any explanation. ( I'll write about this, too, later. )
( 4 ) Red shift between stars.
Another reason which nobody cares. Red shift is not special only for galaxies.
Stars in Milky Way are also observed to have red shift. ( not concern in movement of each star ) and it is called red shift between stars. The cause of this is said to be not the ones of the ( 1 ) ( 2 ) ( 3 ) reasons but cosmic dust which exists between stars.
They say that a lot of cosmic dust which are collected at the disk part of Milky Way, give the shift of observed light a little into red side. It means that galaxy light also can have red shift by cosmic dust between stars. If there is cosmic dust in universal space, even if density of one 1000th or one 10000th of disk of Milky Way, it would be enough to have red shift for Galaxy light. Galaxy light flies several 10000 times or several 100000 times of distance as long as stars in Milky Way. So galaxy light must get the effect of cosmic dust between galaxies.
Conclusion
By ( 2 ) ( 3 ) (4 ), it means that red shift of galaxy is not caused by ( 1 ), Doppler effect. But ( 2 ) and ( 3 ) are said under the circumstance of expansion of space, so they are based on big bang theory. I don't know how they treat Doppler effect.
I think galaxy red shift happens because of ( 4 ) cosmic dust between galaxies. Then, when the distance goes bigger, red shift goes bigger by double. And you don't have to talk about space expansion as if it is like SF story.
Big bang theory supporters say that the reason why Andromeda Galaxy doesn't have red shift is the peculiar movement by two galaxies' gravitation is bigger than speed of space expansion between Andromeda Galaxy and Milky Way. ( Some people say that some galaxies don't have space expansion because of their gravitation. ) But, Andromeda Galaxy and Milky Way are too close to have red shift, I think. The blue shift by Doppler effect caused by the speed of Andromeda Galaxy which is coming closer, is bigger than the red shift by the cosmic dust between them. What do you think? I think this opinion is reasonable.

          Fossil of light 4.       fossil 6

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