Kelvin defended this calculation throughout his life, even disputing Darwin's explanations of evolution as impossible in that time period.In 1898, Marie Curie discovered the phenomenon of radioactivity, in which unstable atoms lose energy, or decay, by emitting radiation in the form of particles or electromagnetic waves.Before so-called radiometric dating, Earth's age was anybody's guess.Our planet was pegged at a youthful few thousand years old by Bible readers (by counting all the "begats" since Adam) as late as the end of the 19th century, with physicist Lord Kelvin providing another nascent estimate of 100 million years.Radiocarbon dating is one such type of radiometric dating.A process for determining the age of an object by measuring the amount of a given radioactive material it contains.) is an earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time.Geology can also refer to the study of the solid features of any terrestrial planet or natural satellite, (such as Mars or the Moon).
It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks.
The Phanerozoic Eon is divided into three such time frames: the Paleozoic, Mesozoic, and Cenozoic represent the major stages in the macroscopic fossil record.
These eras are separated by catastrophic extinction boundaries, the P-T boundary between the Paleozoic and the Mesozoic and the K-Pg boundary between the Mesozoic and the Cenozoic.
Strata Thickness- In the late 1800s, a British geologist estimated that 75 million years has lapsed since the beginning of the Cambrian.
This estimate was based upon the maximum known thickness of strata (from Cambrian to present) divided by the average rate of sedimentation in modern environments. Joly used the salinity of ocean water to determine the age of the earth.