"Pale Blue Dot" author Carl (5)
I believe the answer is:
sagan
'pale blue dot author carl' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sagan that I've seen before include "French authoress" , "Astronomer" , "Author of Bonjour Tristesse, d. 2004" , "US scientist" , "French author" .)