Subject: Are photons perpetual motion machines?

I have read the question and answer Andrew DeVault's "Red Shift, how solid 
is the theory?" 7/13/96 and cannot help but believe that Stephen Murray's 
reply requires a photon to implicitly be a perpetual motion machine. That 
is, a photon that is millions of years old has the same energy as a newly 
generated photon. Being a patent attorney by trade, I have been convinced 
that perpetual motion machines are not physically possible. Yet the theory 
of the expanding universe seems to relies on their very existence.

It would seem to my undisciplined mind that a photon, like any other thing 
in this universe, is subject to the laws of entropy. Thus light from a 
distant galaxy would necessarily loose energy as it travels, thus causing 
an increasing red shift the further it travels and thus cause the same 
uniform red shift that others are using to explain the expanding universe 
theory. Furthermore, just saying that photons are not immune from entropy 
would remove the need for the complex and irregular gravity well 
explanation posed in Stephen Murray's reply.

Is there any evidence that red shift is not due to entropy or other means 
causing photons loose energy as they travel?

Thank you.

Re: Are photons perpetual motion machines?