( ( ( The ages ) ( ( ( of ( Earth ( and ( Moon rocks ) ) ) ) and ) ( of meteorites ) ) ) ( ( are ( measured ( by ( ( the decay ) ( of ( ( long-lived ( radioactive isotopes ) ) ( of ( elements ( that ( ( ( occur naturally ) ( in ( ( ( ( rocks and ) minerals ) and ) ( ( that decay ) ( with ( ( half lives ) ( of ( 700 million ) ) ) ) ) ) ) ) ( ( to ( ( more ( ( than 100 ) billion ) ) years ) ) ( to ( ( stable isotopes ) ( of ( other elements ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS ages)) (PP (PP (IN of) (NP (NNP Earth) (CC and) (NNP Moon) (NNS rocks))) (CC and) (PP (IN of) (NP (NNS meteorites))))) (VP (VBP are) (VP (VBN measured) (PP (IN by) (NP (NP (DT the) (NN decay)) (PP (IN of) (NP (NP (JJ long-lived) (NN radioactive) (NNS isotopes)) (PP (IN of) (NP (NP (NNS elements)) (SBAR (WHNP (WDT that)) (S (VP (VBP occur) (ADVP (RB naturally)) (PP (IN in) (NP (NP (NNS rocks) (CC and) (NNS minerals)) (CC and) (NP (NP (DT that) (NN decay)) (PP (IN with) (NP (NP (NN half) (NNS lives)) (PP (IN of) (NP (QP (CD 700) (CD million))))))))) (PP (TO to) (NP (QP (JJR more) (IN than) (CD 100) (CD billion)) (NNS years)) (PP (TO to) (NP (NP (JJ stable) (NNS isotopes)) (PP (IN of) (NP (JJ other) (NNS elements))))))))))))))))) (. .)))
The ages of Earth and Moon rocks and of meteorites are measured by the decay of long-lived radioactive isotopes of elements that occur naturally in rocks and minerals and that decay with half lives of 700 million to more than 100 billion years to stable isotopes of other elements.
(ROOT (S (NP (DT The) (JJ long-lived) (NNS isotopes)) (VP (VBP require) (NP (NP (NNS thousands)) (PP (IN of) (NP (NP (NNS years)) (PP (TO to) (NP (NN decay)))))) (PP (TO to) (NP (NP (DT a) (JJ safe) (NN level)) (PP (IN in) (NP (DT a) (JJ nuclear) (NN reactor)))))) (. .)))