( ( ( The transfer ) ( of ( energy ( from ( ( the Sun ) ( across ( nearly ( empty space ) ) ) ) ) ) ) ) ( ( -LRB- ( ( remember ( that ( space ( is ( a vacuum ) ) ) ) ) -RRB- ) ) ( ( is ( ( accomplished primarily ) ( by radiation ) ) ) . ) ) )
(ROOT (S (NP (NP (DT The) (NN transfer)) (PP (IN of) (NP (NP (NN energy)) (PP (IN from) (NP (NP (DT the) (NNP Sun)) (PP (IN across) (NP (RB nearly) (JJ empty) (NN space)))))))) (PRN (-LRB- -LRB-) (S (VP (VB remember) (SBAR (IN that) (S (NP (NN space)) (VP (VBZ is) (NP (DT a) (NN vacuum))))))) (-RRB- -RRB-)) (VP (VBZ is) (VP (VBN accomplished) (ADVP (RB primarily)) (PP (IN by) (NP (NN radiation))))) (. .)))
The transfer of energy from the Sun across nearly empty space (remember that space is a vacuum) is accomplished primarily by radiation.
(ROOT (S (NP (DT The) (NN nucleus)) (VP (VBZ is) (VP (VBN comprised) (ADVP (RB primarily)) (PP (IN of) (NP (JJ empty) (NN space))))) (. .)))