Is it common sense that the speed of light is the only constant in space-time, resulting in the fact that to a photon travelling billions of light years to hit the retina the entire trajectory happens instantaneously, although to the the person attached to the retina it took billions of years?
I know this was only an aside to use as an intro to what you really wanted to say about genomes and reproduction, but I think the misunderstanding about science that your aside represents is critical to clear up before trying to tackle evolution.
You ask skeptically if it is common sense that the speed of light being a constant causes a photon to experience a trip of billions of light years as if it were only an instant, while to us it looks like it took billions of years. Well, your premise, that a photon could even have a perception of time, is nonsense. So whatever “common sense” you are appealing to, it does not challenge the facts of Einsteinian Special Relativity, to which you appear to be referring. I suppose what you are really challenging is the much more reasonable conclusion that an object travelling very fast experiences time passing more slowly than objects at rest. Even that scenario requires some qualification and restatement before it can even be considered.
What do we mean by an object experiencing the passing of time? Well, we have lots of ways. Many of them have been built into objects we call clocks. There are candles that burn down, grains of sand falling through a narrow tube of glass, swinging pendulums, oscillating crystals of quartz. All of these “clocks” measure the passage of time. A person aging can also be considered a clock, but probably less accurately than a candle burning down, since people age differently. So for simplicity, let’s stick to inanimate objects. Since your original scenario involved an inanimate photon, that should be no problem.
Next we have your description of a one-way trip taken by the photon. Without some universal sense of “now,” there is no way start a one-way trip taken by a clock and measure, independently of the clock itself, how long its trip took. So if we want to compare a moving clock to a stationary clock, the moving clock has to make a round-trip.
So now we have the following experiment. One clock is stationary and the other clock goes very fast on a round-trip. The clocks start out synchronized. So the nearest actual testable scenario to the one you described is have two clocks and comparing them after one of them goes very fast and comes back to where it started. Your “common sense” would tell you that the clocks would still be synchronized (to within the known stability of the clocks in question). Relativity says otherwise. Not only that, the experiment has been performed a number of times with real clocks, and they do deviate exactly to the extent predicted by relativity. So much for “common sense.”
