What is helium dating
Uranium and thorium in zircons produce helium as a by-product of their radioactive decay. Helium diffusion rates support accelerated nuclear decay.
This helium seeps out of the the zircons quickly over a wide range of temperatures.
Two Swedish chemists, Nils Langlet and Per Theodor Cleve, independently found helium in clevite at about the same time as Ramsay.
Helium makes up about 0.0005% of the earth's atmosphere.
This trace amount of helium is not gravitationally bound to the earth and is constantly lost to space.
And between the two, helium is the second lightest and second most abundant element, being present in about 24% of observable Universe’s elemental mass.
Whereas we tend to think of Helium as the hilarious gas that does strange things to your voice and allows balloons to float, it is actually a crucial part of our existence.