Radiocarbon dating age of the earth
Here’s an example using the simplest atom, hydrogen. Carbon-14 is an unstable isotope of carbon that will eventually decay at a known rate to become carbon-12.Radiocarbon dating uses isotopes of the element carbon. Cosmic rays – high-energy particles from beyond the solar system – bombard Earth’s upper atmosphere continually, in the process creating the unstable carbon-14. Because it’s unstable, carbon-14 will eventually decay back to carbon-12 isotopes.Certain isotopes are unstable and undergo a process of radioactive decay, slowly and steadily transforming, molecule by molecule, into a different isotope.This rate of decay is constant for a given isotope, and the time it takes for one-half of a particular isotope to decay is its radioactive half-life.Because the cosmic ray bombardment is fairly constant, there’s a near-constant level of carbon-14 to carbon-12 ratio in Earth’s atmosphere.Organisms at the base of the food chain that photosynthesize – for example, plants and algae – use the carbon in Earth’s atmosphere.
But when gas exchange is stopped, be it in a particular part of the body like in deposits in bones and teeth, or when the entire organism dies, the ratio of carbon-14 to carbon-12 begins to decrease.
The age of the planet, though, was important to Charles Darwin and other evolutionary theorists: The biological evidence they were collecting showed that nature needed vastly more time than previously thought to sculpt the world.
A breakthrough came with the discovery of radioactivity at the beginning of the 1900s.
Using this technique, called radiometric dating, scientists are able to "see" back in time.
When asked for your age, it's likely you won't slip (with the exception of a recent birthday mistake).
Measuring the uranium-to-lead ratios in the oldest rocks on Earth gave scientists an estimated age of the planet of 4.6 billion years.