A lay ignoramus seeks answers to a simple question of lightshift.
Say "now and now and now" and, irrespective of fast or imperceptible appreciation of a second, at each "now" Universe has situated the earth 20 or so miles further along its circuit of the sun, the sun about 100 miles further in its run around the galaxy, and the galaxy 200-odd miles towards its appointment with Andromeda and 150,000 miles farther from the position which yonder remote galaxies occupied when they issued their light all those seconds ago (of which, more later). That is the evident difference that a single second makes in the progress of Universe just so far as we are concerned, and I hope your use of simple mental arithmetic will safely acquit this point from any hint of 'speculation'.
However, for some microbes, each second is a generation, while for some trees a hundred seconds are equivalent to a very deliberate wink, and even for each individual the rate of perception appreciably alters with age. So the apparent rate of observation makes the experience very different for organisms with different rates of metabolism.
Then what of the situation of the vast majority of Universal material entirely lacking metabolic atomic action? Within our restricted fleeting bubble of consciousness, enabled by our personal biochemical atomic action, our senses are able to perceive the 'action' of only a moving 'here and now' and cannot see universal totality. But in the same way that yesterday, the inscrutable future of the day before, was memorably here, and that the rock beneath our feet, which at one time was the future of a little of the long 'theretofore', now is evidently here, and that all the past visibly has been here without the benefit of our presence, everything of the future, whatever it may be, is also already here in Universe, but our same fleeting bubble of consciousness, involved in the activity only of 'here and now', has not yet arrived spatially to authenticate it.
Thus, invisible to us, here there is an already complete, timeless Universe formed of a single ingredient, of which our trivial experience of 'time', life and observation is a mere implicit concomitant.
As obviously, the past is also still here in Universe, merely our awareness having withdrawn from it and the image of its occurrence fled away at the speed of light beyond possiblity of our vision. So, to spell out the evident, surely it is fair to say that Universe contains all that has ever happened and all that ever will happen, but that our awareness gives us access only to what we term 'the present'. This may be all very obvious, but it is not explained. One might almost presume to ask, if the idea were not so clearly insane, whether our young should be taught something so simple and basic to their sense of reality instead of gangsta rap, and our adults instead of the esoteric formulae of the twin tricky fictions of finance and 'the economy'. As to the question of dark matter and dark energy, if they are essential to the scheme of things and are not perceptible here or in the visible past, then look to the future for them, and if fretting is experienced over the present absence of future, then in the words of Peter Simple's now-famous 'Spanish proverb', "Patience, fleas, the night is long."
So it may be considered that active viewing by our living biochemical material persists spatially over and through other static inorganic material of an already complete Universe, though whether it is interpreted as being so is for conjecture from the differing view-points of each observer. Any resulting opinion will not affect whatever the reality may transpire to be. As such it is for us to change as we may, though those who exercise influence do so unscrupulously for personal gain. That is one thing the rest of us have to change.
Then what exists between the past and now or the past and future? Well, it can only be what we continually experience as 'the present'. We are blind merely to most of Universal past and all of its future.
Be all that as it may, however, let us look at a few nuts and bolts of it. As a living creature now capable of observation, look left and light is seen from those remote galaxies then retreating from us at three-quarters of the speed of light. Look right and light is seen from galaxies similarly then retreating at three-quarters of the speed of light. Because the light is visible simultaneously from both at the same distance, evidently both sets of galaxies existed simultaneously. The fact that we are now in the middle is immaterial. So already ten or twelve billion years ago the galaxies to the left visibly were retreating from the galaxies to the right at one and a half times the speed of light. This is not heretical or difficult to accept if it is acknowledged that space extends with distance, those remote galaxies being carried along in their - to our view - extending space.
Nevertheless, the space in which the galaxies to the left resided, if observed there, would have seemed to be in normal unextended space while, if observation from there had been possible, it would have been space at our present distance that would have appeared equally extended.
So, seen from here, the galaxies to the left, immobile in their locally-standard space, those ten or twelve billion years ago emitted light, which the medium of space between there and here then conducted at the regulation speed of light. This light travelled, always at the approved speed of light, through what to our eyes would seem to have been relatively-contracting space but to itself was just common-or-garden every-day space, and now arrives here at the conventional speed of light but with the wave of its uninterrupted light then set by its retreating source and so here seen as red-shifted. From here the light will now continue at the speed of light and in ten or twelve billion years time arrive at the position where ten or twelve billion years ago the galaxies to the right were receding, then immobile in their - to our observation extending - local space.
So, to free some cross-threaded nuts and bolts, from genuine though only partial incomprehension, it is asked -
1. To what degree will the arriving light be shifted there?
2. Does the - to our eyes - extending space also expand to fill the dimension it enters and, if the words can have any relevance here, will such expansion be 'real' or 'apparent'?
3. If 'real', then do the galaxies that the extending space contains also extend and expand physically in proportion, and, if so, does their mass also increase?
4. Will the light now passing here, always travelling through what to itself is conventional space, eventually be able to catch up with the physical galaxies to the right, even now obviously receding from us at many times the speed of light?
5. And, asking from profound bewilderment, in the likely event that we are not in fact slap bang in the precise centre of everything, and irrespective of any prejudice to big-bangs, super-strings, conflicting mathematical models and such, does the fact of seeing - already ten or twelve billion years ago - galaxies simultaneously twenty or twenty-four billion light-years apart and accelerating not indicate even to non-scientists a Universal lifetime of, by our temporal measurement, at the very least twenty or twenty-four billion years, and size of at least twenty or twenty-four billion light-years (instead of the more probable sixty or seventy billion)? - And if so, then how and why is the notion of the much more recent 'big bang' so willingly embraced by the better-informed scientific community?
6. Would such expansion and the effect of such acceleration not be involved in the question of the alleged elusive dark-energy and -matter? Or,
7. Does the writer have entirely the wrong end of the cosmological stick?
Reference: Reality. Look at the evidence and think for yourself.