Uranium is not the only isotope that can be used to date rocks; we do see additional methods of radiometric dating based on the decay of different isotopes.

relative and radiometric dating-1relative and radiometric dating-14

With rubidium-strontium dating, we see that rubidium-87 decays into strontium-87 with a half-life of 50 billion years.

By anyone's standards, 50 billion years is a long time.

These two uranium isotopes decay at different rates. The half-life of the uranium-238 to lead-206 is 4.47 billion years.

The uranium-235 to lead-207 decay series is marked by a half-life of 704 million years.

The methods work because radioactive elements are unstable, and they are always trying to move to a more stable state. This process by which an unstable atomic nucleus loses energy by releasing radiation is called radioactive decay.

The thing that makes this decay process so valuable for determining the age of an object is that each radioactive isotope decays at its own fixed rate, which is expressed in terms of its half-life.

The existing carbon-14 within the organism starts to decay back into nitrogen, and this starts our clock for radiocarbon dating.

A scientist can take a sample of an organic material when it is discovered and evaluate the proportion of carbon-14 left in the relic to determine its age. Radiometric dating is a method used to date rocks and other objects based on the known decay rate of radioactive isotopes.

Carbon-14 is continually being created in the atmosphere due to the action of cosmic rays on nitrogen in the air.

Carbon-14 combines with oxygen to create carbon dioxide.

With radiocarbon dating, the amount of the radioactive isotope carbon-14 is measured.