American editor's novel is out of this world and potentially earth-shattering (8)
I believe the answer is:
asteroid
'out of this world and potentially earth-shattering' is the definition.
The definition and answer can be both natural objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'american editor's novel' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'novel' indicates anagramming the letters.
'editors' anagrammed gives 'steroid'.
'a'+'steroid'='ASTEROID'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for asteroid that I've seen before include "Rocky body in orbit" , "Minor planet" , "Small celestial body moving around the sun" , "circling rock" , "Any of the small planets revolving around the sun" .)