Unable to destroy luminous patch in space (6)
I believe the answer is:
nebula
'space' is the definition.
The definition and answer can be both groups as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'unable to destroy luminous patch' is the wordplay.
'unable' anagrams to 'NEBULA'.
However, I'm not clear how the anagram is indicated.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for nebula that I've seen before include "Bright patch in sky caused by distant galaxy" , "Hazy light; a slight cloudiness" , "Interstellar gas cloud" , "Gas/dust cloud in space" , "Cloud of gas and dust in outer space" .)