Radiometric dating half life examples

) and they are historically the ones posted to talk.origins more than any others.The young-Earth argument goes something like this: helium-4 is created by radioactive decay (alpha particles are helium nuclei) and is constantly added to the atmosphere.The most direct means for calculating the Earth's age is a Pb/Pb isochron age, derived from samples of the Earth and meteorites.

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.

Helium is not light enough to escape the Earth's gravity (unlike hydrogen), and it will therefore accumulate over time.

The current level of helium in the atmosphere would accumulate in less than two hundred thousand years, therefore the Earth is young.

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.

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.

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.

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