( ( ( Comets and ) ( ( the Origins ) ( of ( the ( Solar ( System ( Current theory ) ) ) ) ) ) ) ( ( holds ( that ( ( our sun ) ( formed ( when ( ( a ( giant ( molecular cloud ) ) ) ( collapsed ( under ( its ( own gravity ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Comets)) (CC and) (NP (NP (DT the) (NNPS Origins)) (PP (IN of) (NP (DT the) (NNP Solar) (NNP System) (JJ Current) (NN theory))))) (VP (VBZ holds) (SBAR (IN that) (S (NP (PRP$ our) (NN sun)) (VP (VBD formed) (SBAR (WHADVP (WRB when)) (S (NP (DT a) (JJ giant) (JJ molecular) (NN cloud)) (VP (VBD collapsed) (PP (IN under) (NP (PRP$ its) (JJ own) (NN gravity)))))))))) (. .)))
Comets and the Origins of the Solar System Current theory holds that our sun formed when a giant molecular cloud collapsed under its own gravity.
(ROOT (S (NP (NP (DT The) (NN sun)) (CC and) (NP (NP (DT all) (NNS objects)) (VP (VBN held) (PP (IN by) (NP (NP (PRP it) (POS 's)) (NN gravity)))))) (VP (VBP make) (PRT (RP up)) (NP (DT the) (JJ solar) (NN system))) (. .)))