What are the differences between the solar system and the Milky Way Galaxy?

Answer 1

A galaxy - including the Milky Way - is a huge collection of solar systems. Each star is a solar system. A star may or may not have planets, but it is already known that many stars do have planets. A galaxy has hundreds of billions of stars, i.e., hundreds of billions of solar systems.

Differences in scale: The nearest star (after the Sun) is Toliman, at a distance of 4.3 light-years - light takes 4.3 years to travel from Toliman to us. That is well outside the Solar System; the farthest objects known in our own Solar System are at a distance of a few light-hours. Our Milky Way, however, has a diameter in the order of 100,000 light-years. It takes light 100,000 years to go across the Milky Way - and there is some reason to believe that nothing can travel faster than light.