Michael,
Can you summarise what evidence was used to come up with the traditional age of dinosaurs? Clearly not C-14, but maybe the dating of the sedimentary rocks?
David
Well, I'm no geologist or palaeontologist, but you only get fossils in sedimentary rock (which covers most of the earth's surface). If you find a dinosaur in sedimentary rock, its is assumed to have died at around the time the sedimentary layer (stratum) was
deposited. You can estimate the absolute age of the rock in the stratum (e.g. of ultimately volcanic origin) using various kinds of non-C14 radioactivity measurements (i.e. of radioactive isotopes having a much longer half-life than C14).
There were, if I recall, early experiments in measuring sedimentation rates with waterborne rock fragments, but I'm not sure whether that's much used today. Thing is, it strikes me that the rock fragments may have been formed well before the organism died. So you can't simply measure the approximate absolute age of the rock and infer that the organism, say a dinosaur, is the same age. As I said, what seems most important to me is when the rock fragments, for example of volcanic origin, were actually
deposited and subsequently cemented together.
If you were to imagine an organism dying today in a flood, it could get covered very rapidly in rock fragments that are many millions of years old. Estimating the age of it thousands of years in the future would be a complicated business. I suppose this would have to include how long it took for it, or mainly its bones, to fossilise. The absolute age of the sedimentary layer or stratum in which it was found wouldn't tell you much.
One can come up with relative ages of sedimentary rock. For the most part, they come to be layed down successively in strata, so that younger strata lie on top of older strata. But it's not always so simple because parts of the earth can move about and even fold over time, so you can find that sometimes younger rocks are below older ones.
So what to do? Well, there are so-called
index fossils that are often found associated with specific types of rock strata; the fossils are of organisms that are assumed to have lived at a certain time, and so the time of deposition is assumed to be in the same period. Hence fossils can be used to date deposition times, but that seems to me to involve a degree of circular thinking. How is it known for sure when the organisms lived in the first place?
There's all sorts of indirect evidences and the experts have come up with what is essentially a generally agreed narrative about what happened and when. But every now and then, something comes up to challenge that narrative, and in the present instance, the discovery of soft tissue in dinosaur bones is one of those. It presents quite a quandary.
On the one hand, C14 decay measurement is deemed to give very accurate results (judged by dating artefacts understood to be of a certain age from human historical data), and so the fossils can be no more than of the order of tens of thousands of years old. But on the other, the established narrative is that all the dinosaurs were wiped out 65m years ago. So either that's false, or, to keep the narrative alive, one has to posit some kind of hitherto unknown process that somehow slows down the rate of C14 decay. That seems a tad dodgy to me, which is why I find it more parsimonous to hypothesise that at least some dinosaurs lived until comparatively recently.
But if they did, that could change the narrative drastically, and who knows how extensive the damage would be. Moreover, the inertia of the scientific establishment, its reluctance to change comfortable narratives and admit error, is well known. Joe and Jane Bloggs generally tend to accept the narratives because they don't have access to all the data, and even if they did, wouldn't know how to interpret it. But, just maybe, neither does the scientific establishment, which relies quite heavily on the consensually agreed narratives to account for empirical observations.
Whilst it's difficult to argue with empirical data, it's easy to simply ignore or hand-wave it away if it's challenging -- we're finding that increasingly in all sorts of fields from cosmology to physics to the mechanics of biological evolution to medicine to psi. But where it can't be ignored, scientists often reach for ad-hoc explanations and the science becomes less and less parsimonious -- becomes riddled with holes, the biggest of which, I'd say, is the simple fact that relativity can't currently be squared with quantum mechanics.
The emperor, it seems, is naked, and the little boys and girls pointing that out are currently being largely ignored. Luckily for us, engineering has to work and be seen to do so, and engineers don't care so much about truth so much as utility. Does a model theory work well enough to produce iphones, satnavs and big-screen TVs? If it does, engineers are happy as gambolling lambs. But that says little about whether underlying theory is an actual representation of reality. It only says that the representation is fit for current purposes.