Earth Science Regents Practice Exam

The Milky Way galaxy is larger than the solar system because it encompasses not only our solar system but also billions of other stars, their respective systems, and various interstellar materials. In essence, the solar system is just a small part of the Milky Way, which spans about 100,000 light-years across and contains an estimated 100 to 400 billion stars. In contrast, Earth is a planet within the solar system, thus making it much smaller in scale. A planetary nebula is a phase in the lifecycle of some stars and refers to the expelled outer layers of a dying star, also significantly smaller than a galaxy. The comet cloud, or Oort Cloud, is a hypothetical region surrounding the solar system full of icy bodies, but it too is much less vast compared to the entirety of the Milky Way. This illustrates the vast scale of galaxies beyond individual solar systems.