If the Universe were expanding and the distance between cosmic objects were increasing, we would have noticed the effect in our cosmic neighborhood. Gravity could counteract and even take over at places but in any case we would not have the STATIC (distances don't change at all) picture we have always been observing.
Cosmologists have found a truly idiotic solution to the above problem: Only the space between galaxies expands; there is no expansion inside galaxies:
Sabine Hossenfelder: "The solution of general relativity that describes the expanding universe is a solution on average; it is good only on very large distances. But the solutions that describe galaxies are different - and just don't expand. It's not that galaxies expand unnoticeably, they just don't. The full solution, then, is both stitched together: Expanding space between non-expanding galaxies." http://backreaction.blogspot.bg/2017/08 ... verse.html
For almost a century no protest has been raised against the idiocy (we all live in Einstein's schizophrenic world, don't we?). In the discussion following Hossenfelder's post "Ambi Valent" is trying to draw the attention to the idiotic implications of "Expanding space between non-expanding galaxies" but Sabine Hossenfelder, a brave but desperately silly Einsteinian, is unable to understand anything.
Not only vacuum friction can slow down light (in a STATIC universe) - the light source can also do so, as photons's journey starts:
"Spatially structured photons that travel in free space slower than the speed of light" Science 20 Feb 2015: Vol. 347, Issue 6224, pp. 857-860
"Physicists manage to slow down light inside vacuum [...] ...even now the light is no longer in the mask, it's just the propagating in free space - the speed is still slow. [...] "This finding shows unambiguously that the propagation of light can be slowed below the commonly accepted figure of 299,792,458 metres per second, even when travelling in air or vacuum," co-author Romero explains in the University of Glasgow press release."
http://www.upi.com/Science_News/2015/01 ... 1422035480
"The speed of light is a limit, not a constant - that's what researchers in Glasgow, Scotland, say. A group of them just proved that light can be slowed down, permanently."
http://www.gmanetwork.com/news/story/41 ... ouching-it
"Although the maximum speed of light is a cosmological constant - made famous by Einstein's Special Theory of Relativity and E=mc^2 - it can, in fact, be slowed down: that's what optics do."
"Glasgow researchers slow the speed of light"
So the essence of the "intrinsic redshift" idea - that the effect can be produced by the source of the light - has been unequivocally proved by experiments:
"Arp argued that the redshift was not due to Hubble expansion or physical movement of the objects, but must have a non-cosmological or "intrinsic" origin." https://en.wikipedia.org/wiki/Halton_Arp
"Expanding Universe "red shift" Myth debunked by Halton Arp using Quasars" https://www.youtube.com/watch?v=nV7JX9BZDMs
Needless to say, Halton Arp is an unperson in Einstein's schizophrenic world:
http://ebooks.adelaide.edu.au/o/orwell/ ... er1.4.html
"Withers, however, was already an unperson. He did not exist : he had never existed."