Ọjọ́orí Ayé ti je sisepinnu pe o je 4.54 billion odun (4.54 × 109 odun ± 1%). Ojoori yi duro lori eri lati inu isojoori radiometriki awon eroja meteoriti be sini o ni bamu mo awon ojoori awon samples atijojulo ti a mo lori aye ati ninu osupa . "Age of the Earth". U.S. Geological Survey. 1997. Retrieved 2006-01-10.  Dalrymple, G. Brent (2001). "The age of the Earth in the twentieth century: a problem (mostly) solved". Special Publications, Geological Society of London 190: 205–221. doi:10.1144/GSL.SP.2001.190.01.14.  Manhesa, Gérard; Allègrea, Claude J.; Dupréa, Bernard; and Hamelin, Bruno (1980). "Lead isotope study of basic-ultrabasic layered complexes: Speculations about the age of the earth and primitive mantle characteristics". Earth and Planetary Science Letters, Elsevier B.V. 47: 370–382. doi:10.1016/0012-821X(80)90024-2.