( ( ( ( ( ( The planet ) ( is ( compared ( to ( Mercury ( , ( Earth ( , ( ( Jupiter and ) Saturn ) ) ) ) ) ) ) ) ) , ) and ) ( ( 51 Peg ) ( is ( compared ( to ( the sun ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT The) (NN planet)) (VP (VBZ is) (PP (VBN compared) (PP (TO to) (NP (NNP Mercury) (, ,) (NNP Earth) (, ,) (NNP Jupiter) (CC and) (NNP Saturn)))))) (, ,) (CC and) (S (NP (CD 51) (NNS Peg)) (VP (VBZ is) (PP (VBN compared) (PP (TO to) (NP (DT the) (NN sun)))))) (. .)))
The planet is compared to Mercury, Earth, Jupiter and Saturn, and 51 Peg is compared to the sun.
(ROOT (S (NP (NNP Mercury)) (VP (VBZ is) (ADVP (RB always)) (ADJP (ADJP (JJR closer)) (PP (TO to) (NP (DT the) (NN sun)))) (SBAR (IN than) (S (NP (PRP it)) (VP (VBZ is) (PP (TO to) (NP (NN earth))))))) (. .)))
Mercury is always closer to the sun than it is to earth.