Big Bang Cosmologists deceptively tell us that Doppler’s Redshift observed in light coming from far off galaxies is the proof of expansion of universe. The fact is that the redshifts they have so observed are not Doppler’s Shifts at all. That is a different kind of redshift which is called Cosmological Redshift. Given the fact that Cosmological Redshift is different from Doppler’s Redshift, scientists should not use the term Doppler’s Effect within the context of the Big Bang Theory. They know that this is different kind of redshift but they continue to use this irrelevant term in official papers and discussions. By using the term Doppler’s Effect, they deceptively project that the Big Bang Model was developed on solid observational grounds because Doppler’s Effect is the physical proof of receding or approaching velocity of any object. Cosmological Redshift, on the other hand, is not the physical proof of receding of any object. Though it is possible that recessional movement may occur under cosmological redshift but it is NOT necessary. There may NOT be recessional movement in redshift-distance relationship. For example there is redshift-distant relation in surface water waves and there is no recessional movement of source of waves. Therefore unlike Doppler’s effect, Cosmological Redshift itself is NOT the proof of recessional velocity of anything. It will amount to proof only if it is supported by direct evidence – such as we have 100 years old redshift data of many galaxies. If there is recessional velocity going on then those galaxies are now at greater distance and there should be greater value of redshift for those galaxies. But all values are same. Big Bang supports say that 100 years are not enough to notice any difference in value. I say ok … lets say few thousand years are enough … but it means that NOW you are without proof … You can acquire proof only after few thousand years … Right now you are without proof. The only ‘proof’ that you tell us is a ‘mathematical proof’ rather than a physical proof. And that ‘mathematical proof’ is also dubious mathematics which is based on manipulated translation.

Doppler’s Shift (redshift) is observed if something is physically moving away from us. Let’s say a far off galaxy is physically moving away from us. The light emitted by the galaxy, right from start, will be redshifted to the full value. With Doppler’s Shift, we get a physical proof that yes the galaxy is physically moving away from us. Doppler’s Effect is essentially redshift–speed relationship. In contrast to this, Cosmological Redshift is redshift–distance relationship. Let’s say an object at near location is moving away with speed 100; at farther distance, speed shall again be 100. At both near and far distance, the Doppler’s Redshift value shall remain the same due to the fact that speed was same. However Cosmological Redshift value shall be different for both the locations because distance is not the same.

(Credit: NASA/JPL-Caltech — taken from this site.)

Please see in this video that due to recessional or approaching velocity of light source, the wavelength is modified exactly at the time of departure. The same modified wavelength, without further alterations is then reached at the receiving point. In Doppler’s redshift, wavelength of light does not increase during the journey of light.

Whereas in ‘Cosmological Redshift’, the far off galaxy is physically NOT moving away from us and normal light is emitted by that galaxy. But during long journey of light, wavelength of light keeps on increasing. The larger distance is covered, the wavelength has become larger. It means if larger distance is covered, the greater redshift is observed at the receiving end. Exact this thing was noted by Edwin Hubble and finally scientists realized that what redshifts they had been observing since second decade of twentieth century were not Doppler’s Shifts but were Cosmological Redshifts.

(Credit: Image permitted to be used by Jesse Witwer)

Above image of surface water waves is the perfect example of linear relationship between wavelength (redshift) and distance. Hubble actually did not say in year 1929 that Universe is Expanding and his actual finding was simply the linear redshift-distance relationship whose perfect example is above depicted wavelength (redshift) – distance relationship of surface water waves.

Since Cosmological Redshift is not the physical proof of receding of galaxies, so Expansionists now say that it is ‘space’ which is expanding. What is the proof of ‘expansion of space’? The proof is only mathematics – i.e. dubious FLRW metric.

Simple finding of Hubble was that “there is linear relation between redshift and distance”.

FLRW only adds an unnecessary bracket and wants us to read Hubble’s simple finding as “there is linear relation between redshift and (increasing) distance.”

‘Increasing distance’ means expansion of space is going on and proof of this (increasing) bracket is FLRW metric itself.