( ( In cosmology ) ( , ( ( ( the role ) ( of ( the ( external agent ) ) ) ) ( ( is ( played ( by ( ( the ( ( ( strong and ) time-dependent ) ( gravitational field ) ) ) ( of ( the ( ( very early ) Universe ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (NN cosmology))) (, ,) (NP (NP (DT the) (NN role)) (PP (IN of) (NP (DT the) (JJ external) (NN agent)))) (VP (VBZ is) (VP (VBN played) (PP (IN by) (NP (NP (DT the) (ADJP (JJ strong) (CC and) (JJ time-dependent)) (JJ gravitational) (NN field)) (PP (IN of) (NP (DT the) (ADJP (RB very) (JJ early)) (NN Universe))))))) (. .)))
In cosmology, the role of the external agent is played by the strong and time-dependent gravitational field of the very early Universe.
(ROOT (S (NP (JJ Strong) (JJ gravitational) (NNS fields)) (VP (VBP are) (ADJP (JJ capable) (PP (IN of) (S (VP (VBG altering) (NP (NP (DT the) (NN rate)) (PP (IN of) (NP (NN time) (NN passing))))))))) (. .)))