Answer:
A galaxy is a collection of stars and interstellar material held together by gravity. The galaxy our Sun lives in is called the Milky Way.
The name `Milky Way' comes from the band of light that is seen overhead on very dark nights.
A thick layer of interstellar dust hides much of the Galaxy from observation by optical telescopes, and astronomers can determine its large-scale structure only with the aid of radio and infrared telescopes, which can detect the forms of radiation that penetrate the hidden matter.