explanations, ruling out some himself. The simplest form of a tired light theory assumes an exponential decrease in photon energy with distance traveled: where is the energy of the photon at distance from the source of light, is the energy of the photon at the source of light, and is a large constant characterizing the "resistance of the space". To correspond to Hubble's law, the constant must be several gigaparsecs. For example, Zwicky considered whether an integrated Compton effect could account for the scale normalization of the above model: This expected "blurring" of cosmologically distant objects is not seen in the observational evidence, though it would take much larger telescopes than those available at that time to show this with certainty. Alternatively, Zwicky proposed a kind of Sachs–Wolfe effect explanation for the redshift distance relation: Zwicky's proposals were carefully presented as falsifiable according to later observations: Such broadening of absorption lines is not seen in high-redshift objects, thus falsifying this particular hypothesis. Zwicky also notes, in the same paper, that according to a tired light model a distance-redshift relationship would necessarily be present in the light from sources within our own galaxy (even if the redshift would be so small that it would be hard to measure), that do not appear under a recessional-velocity based theory. He writes, referring to sources of light within our galaxy: "It is especially desirable to determine the redshift independent of the proper velocities of the objects observed". Subsequent to this, astronomers have patiently mapped out the three-dimensional velocity-position phase space for the galaxy and found the redshifts and blueshifts of galactic objects to accord well with the statistical distribution of a spiral galaxy, eliminating the intrinsic redshift component as an effect. Following after Zwicky in 1935, Edwin Hubble and Richard Tolman compared recessional redshift with a non-recessional one, writing that they These conditions became almost impossible to meet and the overall success of general relativistic explanations for the redshift-distance relation is one of the core reasons that the Big Bang model of the universe remains the cosmology preferred by researchers. In the early 1950s, Erwin Finlay-Freundlich proposed a redshift as "the result of loss of energy by observed photons traversing a radiation field". which was cited and argued for as an explanation for the redshift-distance relation in a 1962 astrophysics theory Nature paper by University of Manchester physics professor P. F. Browne. The pre-eminent