The Milky Way Galaxy is the home galaxy of our solar system. It is a large spiral galaxy containing an aggregation of gas, dust, an estimated 400 billion stars, and thousands of globular clusters and nebulae. The Galaxy's mass is probably between 750 billion and one trillion solar masses, and its diameter is about 100,000 light-years light year is equal to 5,865,696 million miles (9,460,800 million kilometers)). All the objects composing our Galaxy orbit about their collective center of mass, called the galactic center. The Galaxy is bound together by the gravitational attraction between its parts, and its rotational motion prevents it from collapsing on itself.

The Milky Way is a term used to described how the stars of our galaxy appear to the naked eye from a position on the earth, away from the light pollution caused by modern cities. For thousands of years, people looked at the...