. . , . , . : 1) ( ), 2) , , ( ).
- , , . , , , . г , , , , .
, . 5/6 , , - . , .
. , , , . , , . , .
䳿 , . ϳ ϳ , , , ( ). , , 䳿 .
. 232Th 238U, 235U ( 1/2 (1,4 ⋅ 1010), (4,5 ⋅ 109) (7 ⋅ 108) ). ֳ (232Th), (238U) (235U). . . , , 210, 210Pb, 226Ra, 230Th, 138,4 , 22 , 1600 8 ⋅ 104 . , , . . , , . 40K T1/2 = 1,26 ⋅ 1010 87Rb T1/2 = 5 ⋅ 1010 . 㳿 14 T1/2 = 5 730 , ' . , 䳿 , , ~ 3,4 ⋅ 1026 14:
, 238U, 235U, 232Th 40K, α - β-.