(April 25, 2014 at 6:45 pm)Pickup_shonuff Wrote: I'm still failing to grasp how, say for example humans who developed the technology to travel at 99.9% light speed, could travel for 5 light years, say from another planet to ours in that distance, and for us it would appear as though their journey took 5 years, for them only a moment or two? Can light never age? For example, light emitted from the oldest observed stars?
There is no meaning to light aging. The photon experience changes, but not because of time. Let's say a photons is emitted by the surface of a neutron star, travel 1 billion light years, and then hits another neutron star.
To the photon, it would come into being with a certain amount of energy. It would instantly lose a major portion of its energy as it ascends the sides of the gravitational well surrounding the source neutron star, instantly traverse 1 billion light years, and then instantly gain a lot of energy as it descends the the gravitaitonal well surrounding the target neutron star.
