For the first time he was able to exactly measure the age of a uranium mineral.

Perseverance over three years of secret research to develop the radiocarbon method came into fruition and in 1960 Libby received the Nobel Prize for chemistry for turning his vision into an invaluable tool.

The basic principle Carbon has three naturally occurring (n is a neutron and p is a proton) After formation the three carbon isotopes combine with oxygen to form carbon dioxide.

Potassium is a component in many common minerals and can be used to determine the ages of igneous and metamorphic rocks.

The Potassium-Argon dating method is the measurement of the accumulation of Argon in a mineral.

Radioactive elements are unstable; they breakdown spontaneously into more stable atoms over time, a process known as radioactive decay.

Radioactive decay occurs at a constant rate, specific to each radioactive isotope.

Since the 1950s, geologists have used radioactive elements as natural "clocks" for determining numerical ages of certain types of rocks. "Forms" means the moment an igneous rock solidifies from magma, a sedimentary rock layer is deposited, or a rock heated by metamorphism cools off.

It's this resetting process that gives us the ability to date rocks that formed at different times in earth history.

The realisation that radioactive materials emit rays indicated a constant change of those materials from one element to another.

The New Zealand physicist Ernest Rutherford, suggested in 1905 that the exact age of a rock could be measured by means of radioactivity.

The discovery of by the French physicist, Henri Becquerel, in 1896 paved the way of measuring absolute time.