( ( ( The ( ( most obvious ) approach ) ) ( to ( ( the problem ) ( of ( predicting ( ( the motions ) ( of ( the ( heavenly bodies ) ) ) ) ) ) ) ) ) ( ( ( was simply ) ( ( ( ( to ( ( map ( their positions ) ) ( against ( the ( star field ) ) ) ) ) and ) then ) ( to ( ( fit ( mathematical functions ) ) ( to ( the ( changing positions ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (ADJP (RBS most) (JJ obvious)) (NN approach)) (PP (TO to) (NP (NP (DT the) (NN problem)) (PP (IN of) (S (VP (VBG predicting) (NP (NP (DT the) (NNS motions)) (PP (IN of) (NP (DT the) (JJ heavenly) (NNS bodies)))))))))) (VP (VBD was) (ADVP (RB simply)) (S (VP (VP (TO to) (VP (VB map) (NP (PRP$ their) (NNS positions)) (PP (IN against) (NP (DT the) (NN star) (NN field))))) (CC and) (ADVP (RB then)) (VP (TO to) (VP (VB fit) (NP (JJ mathematical) (NNS functions)) (PP (TO to) (NP (DT the) (VBG changing) (NNS positions)))))))) (. .)))
The most obvious approach to the problem of predicting the motions of the heavenly bodies was simply to map their positions against the star field and then to fit mathematical functions to the changing positions.
(ROOT (S (NP (NNP Motion)) (VP (MD can) (VP (VB be) (VP (VBN defined) (ADVP (RB simply)) (PP (IN as) (NP (NP (DT a) (NN change)) (PP (IN in) (NP (NN position)))))))) (. .)))