When light hits these free electrons, it produces the Compton effect red shift. Grote Reber predicted that this interpretation of the red shift would result in a dispersion in the arrival times of extragalactic signals. This time lag for longer wavelengths is shown by Dr. Jay Norris to provide a method of measuring distance to the gamma ray source . Some say that the Compton effect should cause the light to be scattered and distance sources blurred. Note how the Milky Way stars at the edge of the Barnard 68 dust cloud are not at all blurred even though they are dimmed to extinction as their photons are absorbed and scattered.
Dark matter causes light to bend without blurring.
There are a great many problems with the Big Bang Theory that have not been solved. These problems include the idea that there are many objects observed that are older than the time from the big bang, which is variously estimated to be from 10 to 15 billion years ago, with the best estimates being 10 billion years. Stars and globular clusters in our galaxy are thought to be older than 15 billion years and there seem to be similar stars that are seen in galaxies that are many billions of light years away from us and thus apparently formed closer to the time of the big bang. Measurements of the uranium content of stars has produced a minimum age of the universe of at least 12 billion years, whereas the best measurements of Hubble's constant produce an age of 10 billion years. Even our earth is thought to be 5 billion years old, and is expected to exist for another 5 billion years before the sun expands and swallows it up.