To date a radioactive rock, geologists first measure the “sand grains” in the top glass bowl (the parent radioisotope, such as uranium-238 or potassium-40).
They also measure the sand grains in the bottom bowl (the daughter isotope, such as lead-206 or argon-40, respectively).
There are a number of implausible assumptions involved in radiometric dating with respect to long time periods.
One key assumption is that the initial quantity of the parent element can be determined.
Radioactivity was discovered in 1896 by French physicist Henri Becquerel.
By 1907 study of the decay products of uranium (lead and intermediate radioactive elements that decay to lead) demonstrated to B. Boltwood that the lead/uranium ratio in uranium minerals increased with geologic age and might provide a geological dating tool.
All rocks and minerals contain long-lived radioactive elements that were incorporated into Earth when the Solar System formed.
These radioactive elements constitute independent clocks that allow geologists to determine the age of the rocks in which they occur.
Its crust is continually being created, modified, and destroyed.
As a result, rocks that record its earliest history have not been found and probably no longer exist.
Because radiometric dating fails to satisfy standards of testability and falsifiability, claims based on radiometric dating may fail to qualify under the Daubert standard for court-admissible scientific evidence.