( ( As ( light ( travels ( through ( ( the ( Earth 's ) ) atmosphere ) ) ) ) ) ( , ( it ( ( 's ( ( ( ( ( deflected , ) or ) scattered ) , ) ( by ( molecules ( of ( air ( -LRB- ( ( mainly ( ( oxygen and ) nitrogen ) ) -RRB- ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN As) (S (NP (NN light)) (VP (VBZ travels) (PP (IN through) (NP (NP (DT the) (NN Earth) (POS 's)) (NN atmosphere)))))) (, ,) (NP (PRP it)) (VP (VBZ 's) (VP (VBN deflected) (, ,) (CC or) (VBN scattered) (, ,) (PP (IN by) (NP (NP (NNS molecules)) (PP (IN of) (NP (NP (NN air)) (PRN (-LRB- -LRB-) (NP (RB mainly) (NN oxygen) (CC and) (NNS nitrogen)) (-RRB- -RRB-)))))))) (. .)))
As light travels through the Earth's atmosphere, it's deflected, or scattered, by molecules of air (mainly oxygen and nitrogen).
(ROOT (S (NP (NNP Light)) (VP (VBZ is) (VP (VBN scattered) (PP (IN from) (NP (NP (NNS molecules)) (PP (IN in) (NP (PRP$ our) (NN atmosphere))))))) (. .)))