How does the size of the solar system compare with the size of the Milky Way Galaxy?

Answer 1

The Milky Way is approximately 100,000 lightyears from one end to the other. Or approximately 39,000,000,000,000 cubic lightyears. The Solar System is approximately 0.0006 lightyears (322 lightminutes) from one end to the other. Unfortunately I don't know the cubic volume of the solar system so we'll work with a 1D field.

Additionally, a proper anology would require what you consider the solar system. Officially, our solar system is only 50 AU across (0.0006ly or more simply 50 times the distance from the Sun to Earth) however if you include ALL planets, including even Sedna all the way out to the bowshock, which is the true end of the solar system (The bowshock separates the insterstellar medium from the stellar medium), then our solar system is 230AU across (0.003ly). To put the two in perspective, 30-50AU is the distance from the Sun out just past Neptune, around the Kuiper Belt.

Simply put, the Solar System is approximately 0.00000059% the size of the entire galaxy. It's very difficult to find commonplace objects that could be analogous to that size differential. The closest analogy I can think of would be comparing a large grain of sand (10mm) to the total radius of Earth (6,371km). Said grain of sand is approximately 0.000000156% the size, which is actually slightly larger than the differential of the solar system to the galaxy. So think a single grain of sand on a rock the size of Earth.