( ( ( ( They ( happen ( because ( of ( a ( celestial coincidence ) ) ) ) ) ) : ) ( ( although ( ( ( the ( Sun 's ) ) diameter ) ( is ( ( 400 times ) ( greater ( than ( the ( Moon 's ) ) ) ) ) ) ) ) ( , ( it ( ( ( ( is also ) ( ( 400 times ) ( farther away ) ) ) , ) ( so ( it ( ( appears ( the ( same size ) ) ) ( as ( ( the Moon ) ( in ( the sky ) ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (PRP They)) (VP (VBP happen) (PP (RB because) (IN of) (NP (DT a) (JJ celestial) (NN coincidence))))) (: :) (S (SBAR (IN although) (S (NP (NP (DT the) (NNP Sun) (POS 's)) (NN diameter)) (VP (VBZ is) (ADJP (NP (CD 400) (NNS times)) (JJR greater) (PP (IN than) (NP (DT the) (NNP Moon) (POS 's))))))) (, ,) (NP (PRP it)) (VP (VBZ is) (ADVP (RB also)) (ADVP (NP (CD 400) (NNS times)) (RBR farther) (RB away)) (, ,) (SBAR (IN so) (S (NP (PRP it)) (VP (VBZ appears) (NP (DT the) (JJ same) (NN size)) (PP (IN as) (NP (NP (DT the) (NN Moon)) (PP (IN in) (NP (DT the) (NN sky)))))))))) (. .)))
They happen because of a celestial coincidence: although the Sun's diameter is 400 times greater than the Moon's, it is also 400 times farther away, so it appears the same size as the Moon in the sky.
(ROOT (S (NP (NP (DT The) (NN sun)) (CC and) (NP (DT the) (NN moon))) (VP (VBP appear) (S (VP (TO to) (VP (VB be) (PP (IN about) (NP (NP (DT the) (JJ same) (NN size)) (PP (IN in) (NP (DT the) (NN sky))))) (SBAR (IN because) (S (NP (DT the) (NN moon)) (VP (VP (VBZ is) (ADJP (JJR smaller)) (PP (IN in) (NP (NN diameter)))) (CC and) (VP (VBZ is) (ADJP (ADJP (JJR closer)) (PP (TO to) (NP (NN earth)))) (PP (IN than) (NP (DT the) (NN sun))))))))))) (. .)))