Have you heard about, the Tired light theory?
Fritz zwicky in 1929 said that,the cosmological redshift we observes,which is the basic and primary evidence for expanding universe and big bang theory; is due to photons losing energy as they travel through space,literally getting tired. This is the Tired light theory!
Using Planck’s energy equation,the theory postulates that,as the energy decreases,there would be a variation in frequency towards redder side,which is why we gets a redshift.
But the theory fails to explain some other facts.
These tiring light particles,doesn’t seems to obey the time dilation,which is fundamental to them.
The Cosmic Microwave Background radiation,would not be expected to follow a blackbody spectrum 😋
If the tiring happens,distant images must be seen more blurry than the nearer ones;which isn’t. Hubble space telescope gets the farthest images to maximum clarity,just as same as the nearer ones,only the amount of light received matters.