Dating on the earth
Most scientists and many Christians believe that the radiometric dating methods prove that the earth is 4.5 billion years old.
The textbooks speak of the radiometric dating techniques, and the dates themselves, as factual information.
Studies of strata, the layering of rocks and earth, gave naturalists an appreciation that Earth may have been through many changes during its existence.
These layers often contained fossilized remains of unknown creatures, leading some to interpret a progression of organisms from layer to layer.
giving an age for the Solar System and an upper limit for the age of Earth.
It is hypothesised that the accretion of Earth began soon after the formation of the calcium-aluminium-rich inclusions and the meteorites.
It is also difficult to determine the exact age of the oldest rocks on Earth, exposed at the surface, as they are aggregates of minerals of possibly different ages.Radioactivity was discovered in 1896 by French physicist Henri Becquerel.By 1907 study of the decay products of uranium (lead and intermediate radioactive elements that decay to lead) demonstrated to B. Boltwood that the lead/uranium ratio in uranium minerals increased with geologic age and might provide a geological dating tool.In the mid-18th century, the naturalist Mikhail Lomonosov suggested that Earth had been created separately from, and several hundred thousand years before, the rest of the universe. In 1779 the Comte du Buffon tried to obtain a value for the age of Earth using an experiment: He created a small globe that resembled Earth in composition and then measured its rate of cooling.This led him to estimate that Earth was about 75,000 years old.