Rutherford and holmes radiometric dating
From the fragments, scientists calculated the relative abundances of elements that formed as radioactive uranium decayed over billions of years."It was not until the 1950s that the age of the universe was finally revised and put safely beyond the age of the Earth, which had at last reached its true age of 4.56 billion years," Lewis said.
"Physicists suddenly gained a new respect for geologists."For the record, the universe is now thought to have debuted, at least in its latest incarnation, about 13.7 billion ago.
The French physicist Antoine Henri Becquerel (1852-1908) wondered if X rays might be among the energy given off by fluorescent materials.
In 1896 Becquerel discovered that potassium uranyl sulfate (K2UO2 (SO4)2 did create energy that penetrated black paper to expose photographic film.
The Curies found that the radiation was proportional to the Uranium content of the compound.
This indicated that radioactivity was a property of atoms, not molecules.
Furthermore, this energy could penetrate cardboard and even walls to fluoresce barium platinocyanide.
Rontgen used the mathematical symbol for unknown to name this energy X-rays.
This source of energy caused barium platinocyanide coated on paper to luminance.Meanwhile, Arthur Holmes (1890-1964) was finishing up a geology degree at the Imperial College of Science in London where he developed the technique of dating rocks using the uranium-lead method.By applying the technique to his oldest rock, Holmes proposed that the Earth was at least 1.6 billion years old.In 1898 the Polish-French physicist team of Marie Sklodowska Curie (1867-1934) and her husband Pierre (1859-1906) discovered that thorium also gave off radiation.The phenomenon of emitting penetrating, ionizing radiation was given the name radioactivity by the Curies.