Answer:
Astronomers know more about some galaxies than they do about the Milky Way because they are able to observe them from further away. Due to the great distances between galaxies, it is much easier to study galaxies like Andromeda and other distant galaxies than it is to study our own Milky Way galaxy. Additionally, the Milky Way is an active and complex system and is difficult to observe in its entirety, making it difficult to study in detail.