The most common and most likely answer to this crossword clue is the 12 letter word HELIOCENTRIC
H
E
L
I
O
C
E
N
T
R
I
C
Buddy explains!
The straight part
We know that "typical of Galilean ideas" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case typical of galilean ideas = heliocentric.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.
What does HELIOCENTRIC mean?
HELIOCENTRIC adjective- Having the sun at the center/centre; usually in reference to a solar system or orbit.