The initial clues felt scattered. 'Titan' and 'Triton' immediately made me think of mythology.
I considered 'Greek gods' as a possibility, but that theory broke when I saw 'Phobos'.
The reference to Galileo in the final clue was the turning point.
It shifted my focus toward astronomy and celestial bodies.
That clue, 'Ganymede (seen by Galileo)', made me think of Jupiter's moons.
Then I realized that all the clues were celestial objects orbiting planets in our solar system.
The answer is: Moons in our solar system.
In hindsight, the connection is clear: each clue represents a moon orbiting a planet in our solar system.
The Galileo clue was the key to unlocking the puzzle.
It provided the specific context needed to see the common thread.
This puzzle highlights the importance of considering all clues before settling on a solution.
Sometimes the most obvious answer is the one that takes the longest to see.