Most of the argon in the Earth's atmosphere was produced by electron capture of long-lived 40 K (40 K + e− → 40 Ar + ν) present in natural potassium within the Earth.
Sebagian besar argon pada atmosfer bumi dihasilkan dari penangkapan elektron 40K jangka panjang (40K + e− → 40Ar + ν) yang ada dalam kalium alami di bumi.