- September 2nd, 2014, 2:06 pm
#213137
Acknowledging an age for the universe was deemed (at least) conceptually possible, once the Astronomer, Edwin Hubble confirmed, by observation that most of the visible galaxies are receding, from us at ever-increasing velocities. The "ever-increasing" bit, is crucial, because it implies a galaxy's recession velocity is proportional to the age-of-the-universe. By extrapolating backward, that age can now be (presumably) deduced. We should note that this assertion tacitly makes two key assumptions. They are (1): the universe is homogenous; and (2): it is isotropic . Which is, to say the view is essentially the same, in every direction, as seen from every location. There is, therefore no privileged point-of-view.
A consequence of these assumptions is that every location in space (and time) is actually the center-of-the-universe. Maintaining the homogeneity, and the isotropy for each such location requires a high state of entropy. So, when "extrapolating backward", to the putative beginnings of the universe, we're actually not talking about time, as such (That's because the arrow-of-time is derivative from entropy, and not the other way around). The paradox of trying to date the universe is that information (such as the age-of-the-universe tends to get scrambled, as entropy increases. And yet, here we have a significant piece of information just neatly popping out, rather than being scrambled, as it should. The real problem is that both time, and entropy are being used as fundamental concepts. They, however are not.
Any claims regarding the age-of-the-universe run up against a unique problem. In measuring the age of, let's say a person, it's not necessary to investigate all of the changes-in-entropy, on a "cellular level". You just refer to a calendar, and compute the requisite age. But, even so straight-forward a methodology conceals a deal-breaking flaw. For example: are you measuring sideral, or diurnal time? These different temporal reference frames each represent different entropies. That's important because, remember entropy is what accounts for the arrow-of-time. The discrepancies resulting from using the sun, as opposed to the stars fo determining the periodicity-of-time may not matter, so much, to an octogenarian. However, discrepancies on a cosmic scale would matter. And, on such a truly cosmic scale, the lack of a privileged point-of-view also implies there is no privileged state-of-entropy.
If the universe were maximally efficient in converting heat to work , then (in principle) we might possibly calibrate time , in terms of a privileged entropy state. But, it's not; so, we can't. You'll note that this is tantamount to finding a viable approximation to Hubble's Constant. We can't do that either, however (at least, not without making some gratuitous assumptions). Ok; so we can't determine the age-of-the-universe. But, can we not agree that it does, at least have an age? Sadly, no. We can't measure time (except in a highly restricted, parochial sense), apart from having that privileged state-of-entropy , which we've been denied. But, why then does the universe seem to have an age? Why does the horizon appear to separate the earth from the sky? Artifacts-of-perception aren't substantive. And, as long as " the age-of-the-universe is homogeneous, and isotropic, there's no reason why it, too can't be an artifact-of-perception. In that case, asking what is the age-of-the-universe becomes a meaningless question.