In 1654 an Irish archbishop calculates, on the basis of Biblical texts, that the Land would have if formed to the 9 hours of day 26 ofOctober of 4004 B.C. Today already knows that the Land has about 5 billion years. The scientific dating is made from the age of the Universe and the study of the rocks of the terrestrial crust. According to theory of Big Bang, the Universe would have if formed it has 15 billion years and the galaxies it has about 13 billion. The first stars start to appear 4 billion years after Big Bang.
Dating of rocks - to calculate the age of a rock she is necessary to add the time of its formation in the interior of the planet, the period of esfriamento (that it can arrive the 500 a thousand years) and the time that it leads to appear in the crust. In the dating of rocks the scientists identify in its composition radiativos elements. One knows that all radiativo element (unstable isotope) if transforms of course into a steady isotope. The maximum time of transformation also is a known 0 variable. Thus, it is possible to calculate the age of a rock investigating how much still it remains of the radiativo element.