What is relative and absolute dating dressage swimmers dating
Consider the following analogy: a clockmaker sells us an electric clock, a pendulum clock, and a spring-driven clock, and guarantees that they are shockproof.
Skeptical of the clockmaker's claim, we subject the clocks to shock: we shake them, drop them, hit them with hammers and shoot them out of a cannon.
There is no particular reason to suspect that this will turn out to be the case when it comes to the laws underlying absolute dating; nonetheless, an argument from principle alone can never be entirely convincing. You will recall from our discussion of sea floor spreading that the sea floor spreads out from mid-ocean rifts, and so ought to be younger nearer the rifts and progressively older further away from them.
What is more, we can measure the rate of spreading directly by GPS, SLR, and VLBI.
So in the U-Pb method, we check that the two uranium isotopes produce concordant dates.
In the Ar-Ar method, we check that step heating yields the same date at every step.
It has also been possible to test Ar-Ar dating against the historical record, since it is sufficiently sensitive to date rocks formed since the inception of the historical record.
But it is equally far-fetched to imagine that three different mechanisms interfered with the three processes in such a way as to leave the dates concordant; that would require either a preposterous coincidence, or for natural processes to be actually conspiring to deceive us: an idea which is, if anything, even more preposterous. But in this case there is a perfectly reasonable and straightforward explanation for why the dates are concordant, namely that they are correct.
Science, since it concerns just one universe with one set of laws, constitutes a seamless whole; we cannot unpick the single thread of absolute dating without the whole thing beginning to unravel.
Still, it has happened in the past that scientists have thought they'd got hold of a law of nature and then found out it was false.
It is hard to see this as a coincidence; it is equally hard to think of some alternate explanation of why we can correlate isotope ratios or sclerochronological data with the relative order of rocks as deduced from stratigraphic methods — other than the straightforward explanation that absolute dating is producing the right dates.
In our discussion of radiometric dating, we have seen that many, indeed most, radiometric methods are self-checking.