(S (S (SBAR (IN While) (S (BASENP (PRP it)) (VP (ADVP (RB successfully)) (VP (VBZ explains) (NP (NP (BASENP (JJ many) (JJ strange) (NNS behaviors)) (PP (IN in) (BASENP (NN space)))) (COMMA ,) (PP (IN such) (PP (IN as) (NP (NP (BASENP (DT the) (JJ slow) (NN shifting)) (PP (IN of) (NP (BASENP (DT the) (NN orbit)) (PP (IN of) (BASENP (NNP Mercury)))))) (CC and) (NP (NP (BASENP (DT the) (NN bending)) (PP (IN of) (BASENP (NN light)))) (PP (IN by) (NP (BASENP (JJ massive) (NNS objects)) (PP (IN such) (PP (IN as) (BASENP (JJ black) (NNS holes))))))))))))))) (COMMA ,) (S (S (VP (VP (VBG testing) (BASENP (DT the) (NN theory))) (PP (IN on) (BASENP (NNP Earth))))) (VP (VBZ has) (VP (ADVP (RB always)) (VP (VBN been) (ADJP (JJ difficult) (PP (JJ due) (PP (TO to) (NP (BASENP (DT the) (JJ small) (NN scale)) (PP (IN of) (NP (NP (BASENP (NN relativity) (POS 's)) (NNS effects)) (PP (IN in) (BASENP (JJ everyday) (NN life)))))))))))))) (PERIOD .))