What is uranium 235 dating

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.

Some of these rocks are sedimentary, and include minerals which are themselves as old as 4.1 to 4.2 billion years.

Rocks of this age are relatively rare, however rocks that are at least 3.5 billion years in age have been found on North America, Greenland, Australia, Africa, and Asia.

While these values do not compute an age for the Earth, they do establish a lower limit (the Earth must be at least as old as any formation on it).

This lower limit is at least concordant with the independently derived figure of 4.55 billion years for the Earth's actual age.

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.

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.

Unfortunately, the age cannot be computed directly from material that is solely from the Earth.

There is evidence that energy from the Earth's accumulation caused the surface to be molten.

It looks like this: Most of the other measurements for the age of the Earth rest upon calculating an age for the solar system by dating objects which are expected to have formed with the planets but are not geologically active (and therefore cannot erase evidence of their formation), such as meteorites.

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