Dating rocks using radioactive isotopes is called
We know the Earth must be at least as old as any rock on it.
Unfortunately, none of the original rocks still exist, so scientists had to use less direct evidence to determine the age of the Earth.
Radiometric dating works best on igneous rocks, which are formed from the cooling of molten rock, or magma.
As magma cools, radioactive parent isotopes are separated from previously formed daughter isotopes by the crystallization process.
The fourth, lead 204, is not the result of radioactive decay.
After one half-life, 50 percent of the original parents remains; after two, only 25 percent remains, and so on.
Decay curve of a radioactive element with a half-life equal to one time unit.
The discovery gave scientists a tool for dating rocks that contain radioactive elements.
Many elements have naturally occurring isotopes, varieties of the element that have different numbers of neutrons in the nucleus.
Search for dating rocks using radioactive isotopes is called:
The oldest rocks and soils from the moon are about the same age--4.6 billion years old.