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First, I want to thank you for one of the first well thought out, intelligent, reasoned, non-confrontational answers I have received from an evolutionist on one of these threads.

Secondly, if we have those “few” examples of carbon dating gone wrong, how can the rest stand up to science? Are most of them not too old to have any verification of their age? What standard could scientists possibly use to prove the other “thousands of millions” are correct.

And last, “Uranium goes through a process that takes billions of years on it’s way to becoming lead.”

So now are we saying the earth is billions of years old? That’s the first I heard of that.

If you will not accept anything except perfect results, that is your perogative. Are you willing to apply that same standard equally outside of the context of the current questions? Will you refuse to take any drug prescribed by you doctor that has any potential unwanted side effects, or refuse to accept that we can safely store long half-life nuclear waste until doing it has actually been demonstrated (that will take several thousand years)?. If NASA screwed up and blew up a rocket, does that mean we can never trust them to launch another one?

You can do that if you want, but is that honestly a practical constraint to put on science, and can we realistically hold them to that standard?

So now are we saying the earth is billions of years old? That’s the first I heard of that.

4.5 Billion years has been the accepted estimate for quite some time.

pubs.usgs.gov/gip/geotime/age.html

So now are we saying the earth is billions of years old? That’s the first I heard of that.

The most direct means for calculating the Earth's age is a Pb/Pb isochron age, derived from samples of the Earth and meteorites. This involves measurement of three isotopes of lead (Pb-206, Pb-207, and either Pb-208 or Pb-204). A plot is constructed of Pb-206/Pb-204 versus Pb-207/Pb-204.

If the solar system formed from a common pool of matter, which was uniformly distributed in terms of Pb isotope ratios, then the initial plots for all objects from that pool of matter would fall on a single point.

Over time, the amounts of Pb-206 and Pb-207 will change in some samples, as these isotopes are decay end-products of uranium decay (U-238 decays to Pb-206, and U-235 decays to Pb-207). This causes the data points to separate from each other. The higher the uranium-to-lead ratio of a rock, the more the Pb-206/Pb-204 and Pb-207/Pb-204 values will change with time.

If the source of the solar system was also uniformly distributed with respect to uranium isotope ratios, then the data points will always fall on a single line. And from the slope of the line we can compute the amount of time which has passed since the pool of matter became separated into individual objects. See the Isochron Dating FAQ or Faure (1986, chapter 18) for technical detail.

A young-Earther would object to all of the "assumptions" listed above. However, the test for these assumptions is the plot of the data itself. The actual underlying assumption is that, if those requirements have not been met, there is no reason for the data points to fall on a line.

The resulting plot has data points for each of five meteorites that contain varying levels of uranium, a single data point for all meteorites that do not, and one (solid circle) data point for modern terrestrial sediments. It looks like this:

Dalrymple, G. Brent, 1986. Radiometric Dating, Geologic Time, And The Age Of The Earth: A Reply To "Scientific" Creationism, U.S. Geological Survey Open-File Report 86-110. 76 pp