This assumption is backed by numerous scientific studies and is relatively sound.However, conditions may have been different in the past and could have influenced the rate of decay or formation of radioactive elements.Help us reduce the maintenance cost of our online services.Because your computer is running an older version of internet browser, it no longer meets the features of modern websites.Imagine we have an undiscovered element, Parentium, that has a radioactive isotope, Parentium-123, which decays to stable Daughterium-123.This is the only way Parentium-123 decays, and there is no other source of Daughterium-123.
There are over forty such techniques, each using a different radioactive element or a different way of measuring them.
Radiometric dating methods are the strongest direct evidence that geologists have for the age of the Earth.
All these methods point to Earth being very, very old -- several billions of years old.
The rules are the same in all cases; the assumptions are different for each method.
To explain those rules, I'll need to talk about some basic atomic physics. Hydrogen-1's nucleus consists of only a single proton.