The universe is vast. The Earth seems large, yet when examined on a cosmic scale, it is like a spec of dust, even less than a grain of dust. The sun itself is large enough to hold about one million Earths. And the sun is only an average star in a galaxy containing many, many stars in a universe of many, many galaxies.
If we stop to think about it, the vastness of the universe is amazing. While we go about our day-to-day business, we may think of the Earth as being the entire realm of reality. Yet this whole planet is like a spec of dust in the solar system. And the solar system is like a spec of dust when compared with the galaxy. And the galaxy—there are clusters of galaxies, and even superclusters.