I came across a NASA answer to this question and although I am order of magnitudes dumber than the PHD that answered it he left out the whole “photons aging” part:
“These photons travel through the universe until they encounter something to interact with…. for example, our eyes or our telescopes. They do not “age”. FROM: http://helios.gsfc.nasa.gov/qa_sp_en.html#photgo“
As a thought experiment as a little kid I imagined a planet that was packed with gun barrels, as closely together as possible and as small as possible. When I fired those guns (in my mind) I could hit stuff close to me but not far away…no matter how small my guns were! In the same way photos dont age per se but they do spread out. We are talking about a single photon essentially being a wavefront progressively getting wider and wider as it travels to something like thirty feet wide. That 30 billion year old wave hits your eyeball and (at some unknown point) the whole shebang collapses and you perceive a single freakin photon!
Of course, this is just what the science of religion tells me. They are so unsure their answer changes all the time but it is a heck of a lot more interesting that what my pastor had to say about the subject.
Of course this post is totally glossing over the whole wave/particle duality but it is easier to just have faith on that issue, call it a wavicle and get on with your day. (insert props to Alan Watts talk about gooey prickles and prickly goo) The universe is stranger than you can possibly imagine, get over yourself.
Want more gooey prickles? How about prickly goo? This little video will sort that out in no time: