Volatile stuff, it's out there! (5)
I believe the answer is:
ether
'volatile stuff' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'out there' is the wordplay.
'out' indicates an anagram.
'there' is an anagram of 'ETHER'.
'it's' is the link.
Can you help me to learn more?
(Other definitions for ether that I've seen before include "Colourless, highly flammable liquid" , "There goes the anaesthetic" , "number" , "Anaesthetic; clear sky (poetic)" , "Volatile organic liquid once used as a general anaesthetic" .)