Original sentence: Gas and dust are deemed unlikely causes of tired light, because it is generally thought that they reflect photons while preserving their trajectory, rather than decreasing their frequency.Most physicists and astronomers do not believe that such an effect can account for cosmological redshifts, and believe the standard explanation that Hubble's law redshift is due to an expanding universe.Photon interactions are also seen as an unlikely cause of tired light, as they would most likely cause as many blue shifts as red shifts
Edited sentence: Gas and dust are unlikely causes of tired light, because they reflect photons rather than decreasing their frequency while preserving their trajectory.Most physicists and astronomers do not believe that such an effect can account for cosmological redshifts, and believe the standard explanation that redshift is due to the Hubble's law redshift of an expanding universe.Photon interactions are also an unlikely cause of tired light, as they would most likely cause as many blue shifts as red shifts