In 1929, Hubble formulated a law that the velocity of a receding galaxy is proportional to its distance to the Earth. The Hubble relation held in all directions suggesting to de Sitter that the Universe was consistent with the expansive metric of Einsteins theory of general relativity. However, others thought the Hubble redshift was caused by mechanisms without Universe expansion. Zwicky proposed that galaxy photons redshift because they lose energy as they scatter upon collision with cosmic dust particles (DPs) before entering the Earth, a redshift theory called Tired Light. See www.en.wikipedia.org/wiki/Tired_light. Recently, Ashmore extended Tired Light to loss of energy in galaxy photons upon collisions with electrons. See www.lyndonashmore.com/.

Objections to Tired Light theories are generally based on the argument that scattered light should blur the galaxy image, and therefore are dismissed because the images are clear and not blurred. See www.astro.ucla.edu/~wright/tiredlit.htm. However, claims that Tired Light theories do not explain all the predictions of Big Bang cosmology should be set aside because there is no mandate in science that any theory must totally stand alone, e.g., the anisotropy of the cosmic microwave background (CMB) in the current epoch may be simply explained by the static Universe in the current epoch having nearly uniform temperature everywhere of about 2.726K.

Alternative QED Induced Light Theory

An alternative to the Hubble and Tired Light theories is the theory of QED induced redshift caused by the absorption of galaxy light in DPs. QED stands for quantum electrodynamics. See www.nanoqed.org at “Dark Energy and Cosmic Dust” and “Reddening and Redshift”, 2009. QED theory asserts the redshift Z is spontaneous upon the absorption of light. Here Z = (Lo - L)/L, where L is the wavelength of galaxy light and Lo is the wavelength of the light emitted from the DP.

QED induced redshift may be understood by treating the absorbed galaxy photon as electromagnetic (EM) energy confined within the DP geometry. Recall from quantum mechanics (QM) that photons of wavelength Lo are created by supplying EM energy to a QM box with walls separated by Lo/2. For a spherical DP of diameter D, the QED photons are produced at a wavelength Lo = 2Dn, where n is the index of refraction which for the typical DP of amorphous silicate has n = 1.45. Hence, DPs having D = 0.25 microns redshift the Lyman-alpha line at 0.121 microns to a red line at 0.725 microns with Z ~ 5. If the QED induced redshift in DPs at Z = 5 is erroneously interpreted by the Hubble law, the galaxy recession velocity is 95 % of the speed of light when in fact the Universe is not expanding.

Conclusions

1. The measured Hubble redshift Z is caused by DPs and has nothing to do with an expanding Universe. DPs make moot the existence of dark energy because it is no longer necessary in a static Universe.

2. Tired Light theories based on scattering are likely to produce blurring of the object image. QED theory based on absorption and not scattering do not produce blurring.