( ( In fact ) ( ( the ( upper atmosphere ) ) ( ( ( ( extends ( much ( further out ) ) ) , ) ( into ( the thermosphere ) ) ) . ) ) )
(ROOT (S (PP (IN In) (NP (NN fact))) (NP (DT the) (JJ upper) (NN atmosphere)) (VP (VBZ extends) (ADVP (RB much) (RBR further) (IN out)) (, ,) (PP (IN into) (NP (DT the) (NN thermosphere)))) (. .)))
In fact the upper atmosphere extends much further out, into the thermosphere.
(ROOT (S (NP (NNP Thermosphere)) (VP (VBZ is) (NP (DT the) (JJ upper-most) (NN atmosphere))) (. .)))