It is exactly that: Pluto is a very tiny astronomical object. Galaxies, nebulae, and such are much further away than Pluto, but that is more than made up for by how mind-boggingly large they are. For example, The Andromeda Galaxy is about six full moons wide as viewed from Earth[1].
[1]: http://www.slate.com/blogs/bad_astronomy/2014/01/01/moon_and...