%0 Journal Article %T Is the expansion of universe accelerating or the Photons decelerating? %A Hasmukh Tank %J - %D 2015 %R 10.14419/ijaa.v3i1.4531 %X Astronomical observations of the cosmological red-shift are currently interpreted in terms of ¡®expansion of universe¡¯ and ¡®accelerated-expansion of the universe¡¯, at the rate of H0 c; here H0 is Hubble¡¯s constant, and c is the speed of light. Whereas a straight-forward derivation presented here suggests that: rather it is the photon which is decelerating, at the rate of H0 c. Such a deceleration of photons can be caused by virtual electrons, positrons and pi-mesons, contained in the extra galactic quantum vacuum, because: they do have gravitational-acceleration of the same order as H0 c at their ¡°surfaces¡±; or by decay of a photon into a lighter photon and a particle of mass h H0 / c2. Tired-light interpretations of the cosmological red-shift¡¯ were so far considered as not compatible with the observations of ¡®time-dilation of super-novae light-curves¡¯; so in a paper titled: ¡°Wave-theoretical insight into the relativistic ¡®length-contraction¡¯ and ¡®time-dilation of super-novae light-curves¡¯¡± (Tank, Hasmukh K. 2013), it has been already shown that any mechanism which can cause ¡®cosmological red-shift¡¯ will also cause ¡®time-dilation of super-novae light-curves¡¯. Therefore, we now need not to remain confined to the Big-Bang model of cosmology. %U https://www.sciencepubco.com/index.php/IJAA/article/view/4531