Not the same somehow on earth (7)
I believe the answer is:
another
'not the same' is the definition.
(I've seen this before)
'somehow on earth' is the wordplay.
'somehow' indicates anagramming the letters.
'on'+'earth'='onearth'
'onearth' anagrammed gives 'ANOTHER'.
(Other definitions for another that I've seen before include "Somebody else" , "On earth (anag.)" , "A different (thing)" , "Additional: alternative" , "Someone else" .)