( That ( ( ( is ( ( ( ( ( ( ( about ( six minutes ) ) , ) or ) ( one percent ) ) , ) longer ) ( ( than ( the radio ) ) ( rotational period ) ) ) ) ( measured ( by ( ( ( the ( Voyager ( 1 ( and ( Voyager ( 2 spacecraft ) ) ) ) ) ) , ) ( which ( ( flew ( by Saturn ) ) ( in ( ( 1980 and ) 1981 ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT That)) (VP (VBZ is) (ADVP (ADVP (NP (NP (RB about) (CD six) (NNS minutes)) (, ,) (CC or) (NP (CD one) (NN percent)) (, ,)) (JJR longer)) (PP (IN than) (NP (DT the) (NN radio)) (NP (JJ rotational) (NN period)))) (VP (VBN measured) (PP (IN by) (NP (NP (DT the) (NNP Voyager) (CD 1) (CC and) (NNP Voyager) (CD 2) (NNS spacecraft)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBD flew) (PP (IN by) (NP (NNP Saturn))) (PP (IN in) (NP (CD 1980) (CC and) (CD 1981)))))))))) (. .)))
That is about six minutes, or one percent, longer than the radio rotational period measured by the Voyager 1 and Voyager 2 spacecraft, which flew by Saturn in 1980 and 1981.
(ROOT (S (NP (DT The) (NN voyager) (CD 1) (NN spacecraft)) (VP (VBD visited) (NP (NN saturn)) (PP (IN in) (NP (CD 1980)))) (. .)))