red shift/blue shift in twinkling stars?

Refraction doesn't change the color of light, only the direction. The color you see in a twinkling star is the color that is being directed toward you at the moment. The rest of the colors have been bent off to land in your neighbors lawn, for example. With twinkling, you have red and blue, but no shift. The spectrum isn't shifted, just part of it is missing, same as if you viewed it through blue cellophane. It's very easy with a spectrogram to tell the difference.

In particular, there are lines in the spectrum that occur at certain frequencies because of the way light at those frequencies interacts with matter. If there were twinkling or a twinkling-like effect, you will just see some lines missing along with the whole part of the spectrum where they're found. The remaining lines will be at their normal frequency. With redshift or blueshift, the whole pattern of lines is shifted and the lines appear at different frequencies than they normally do. If you take a long exposure with the spectrogram, you'll get the different parts of the spectrum at different times as the star twinkles, but you'll be able to see the whole spectrum in the exposure and see where the lines are.

Shifted lines cannot be explained by the lines originally forming at shifted frequencies. They must form at their normal frequencies and then be shifted. The shifting cannot be accomplished by any absorption or refraction process.

There are alternative theories. Compton scattering does achieve a shift of frequency, but normally it produces a wide range of shifts, not a perfect shift of each line by exactly the same amount. Some hacked up situation might be describable where Compton scattering produces the redshift, but why make up a complicated explanation when the simple one works? The relativistic explanation of redshift is simple and also produces a regular pattern in terms of distance vs. recession velocity.

The colours we see in twinkling stars have nothing to do with the star's motion. The colours are due to the starlight being scattered and refracted by the atmosphere.

You have confused redshift as it relates to the distance of GALAXIES and the expansion of the universe with the redshift that is due to motion away from us.

None of the stars in our galaxy participate in the expansion of the universe. The only stars that would show expansion redshift would be supernova in distant galaxies (and we wouldn't see those in the night sky without massive telescopes).

The stars we see in the night sky are all within a few thousand light years of Earth and are NOT in the distant universe. And while it sounds like a long distance, its very close cosmologically speaking.

The changes of hue in twinkling is NOT a shifting of wavelength. It is an effect of refraction, caused by turbulence in the air (the light from the star crosses different layers of light, at different temperatures and densities, and the relative position of these layers keeps changing. These layers act like prisms which break the light of the star and spreads it our in spectrum: you eye sees whatever color happens to be pointing towards it at that second. The next second, as the layers move, the spectrum shifts and a different color is pointing at your eye.

The "tired light" theory (explaining cosmological redshift by something other than expansion of space - for example, unseen material in space) was tried roughly 50 years ago. By the 1970s it had pretty well been dropped. I remember attending a meeting among profesisonal astronomers where one astronomer tried to convince others that the tired light theory was still useful, and he was booed. There is no way that intervening matter can shift the wavelength of light. It can change it completely and predictably, but not shift it (there is a difference).

The different colours in "twinkling" isn't called redshift or blueshift. It's just twinkling, or "scintillation" if you have more time. It is the case, though, that matter can affect how we see nearby stars. The light of some stars is attenuated by gas and dust in our line of sight.

But it's completely different to redshift, which isn't seen in stars but only in the most distant galaxies. Redshift is _defined_ as being caused by distant objects moving away at high speed.

No, though you're running with a "common sense" interpretation of what redshift is and how it's measured, your conception of it is somewhat inaccurate. Redshift is not merely a measure of the reddening of a light. In redshift, landmark emission/absorption lines in the observed spectra of the star (such as the hydrogen-alpha line) are literally shifted towards the red end. Atmospheric interference simply generates more absorption lines, which can be filtered out.

Then there's the matter that space telescopes like Hubble have given us the ability to make redshift observations unhindered by atmosphere.

Redshifting is something that mainly concerns distant galaxies, with the redshift occurring not because the galaxies are "racing away" from us (they're actually relatively stationary compared to us), but because space is expanding between us and them.

Just about any star you see at night is going to be within a few thousand light-years, at *most*, our tiny corner of our own galaxy. Redshifting or blueshifting are not going to be part of any explanation for the colour shifting. That is explained simply by atmospheric disturbance. Were you to view these stars from space, they would not twinkle, and their colour would remain constant.

There is no red shift or blue shift involved in scintillation. It is a result of refraction, and a spectrometer will not record any shifting of wavelengths involved. There have been those who claim red shifting is a result of Compton scattering, but they are simply ignorant as well. There is no shifting of wavelengths involved in that either. Red shifting clearly indicates a reduction in energy, which is impossible under the conservation of energy law unless the source is moving away at high speed or producing immense gravity.

If the dopplering effect was caused by material scattered in space, one would expect that at a given distance, one galaxy would doppler more than another since material is not evenly distributed in space, but the reality is that for a given distance, the doppler effect is relatively the same magnitude in every direction.

Matter doesn't shift wavelengths to the red or blue. It just refracts and attenuates it. The multi-color effects you see in twinkling is just a prismatic effect, not a shift.

It has NOTHING to do with red shift. The twinkling is cause be Earths atmospheric conditions. Nothing more.