Galileo was an Italian scientist who help to develop the

TELESCOPE

Explanation:

Of all of his telescope discoveries, he is perhaps most known for his discovery of the four most massive moons of Jupiter, now known as the Galilean moons: Io, Ganymede, Europa and Callisto. When NASA sent a mission to Jupiter in the 1990s, it was called Galileo in honor of the famed astronomer.

i believe that the answer to the question provided above is that  establishing smaller ethnic communities within larger communities  gives more chance for people to know each other more but this might lead to the  conflict between groups.

nativists tried to get rid of the immigrants as they thought they were going to ruin the u.s.