system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can we only see so many stars in our own galaxy, but we can see the Andromeda Galaxy billions of light-years away with the naked eye?
gpt
That's kind of like asking why you can see the moon, but why can't you see a grain of sand 100 yards away. The sand is much closer, but the moon is much bigger.

Andromeda Galaxy is 220,000 light years across and contains a trillion stars. A typical star is 1.4 million kilometers across. That means a star is 0.00000000006726% as big as a galaxy. Also, Andromeda is "only" 2.5 million light years away - not billions of light years.