The most common and most likely answer to this crossword clue is the 8 plus 7 letter word PARTICLE PHYSICS
I've seen this crossword clue in The Guardian
P
A
R
T
I
C
L
E
P
H
Y
S
I
C
S
More clues leading to the result PARTICLE PHYSICS
Buddy explains!
The straight part
We know that "Science" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case science = particle physics.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.