( ( ( The fact ) ( that ( they ( heard ( two ( sonic booms ) ) ) ) ) ) ( ( ( ( suggests ( that ( ( the object ) ( may ( have ( exploded ( prior ( to ( reaching ( the earth ) ) ) ) ) ) ) ) ) ) , ) ( as ( ( many meteors ) do ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN fact)) (SBAR (IN that) (S (NP (PRP they)) (VP (VBD heard) (NP (CD two) (JJ sonic) (NNS booms)))))) (VP (VBZ suggests) (SBAR (IN that) (S (NP (DT the) (NN object)) (VP (MD may) (VP (VB have) (VP (VBN exploded) (ADVP (RB prior) (PP (TO to) (S (VP (VBG reaching) (NP (DT the) (NN earth))))))))))) (, ,) (SBAR (IN as) (S (NP (JJ many) (NNS meteors)) (VP (VBP do))))) (. .)))
The fact that they heard two sonic booms suggests that the object may have exploded prior to reaching the earth, as many meteors do.
(ROOT (S (NP (NP (NNS Objects)) (PP (IN on) (NP (NN earth)))) (VP (VBP have) (NP (NP (CD two) (NNS forces)) (VP (VBG acting) (PP (IN on) (NP (PRP them))) (PP (IN at) (NP (DT all) (NNS times)))))) (. .)))