See, e.g., holoduke's comment in this thread. The main tool that I (I'd say "we", but I know that different folks visualize differently) have for understanding

See, e.g., holoduke's comment in this thread. The main tool that I (I'd say "we", but I know that different folks visualize differently) have for understanding the scale of the universe is analogy. It's absolutely non-trivial to understand (grasp / grok / missing English verb) this sort of thing -- but it's absolutely possible to continue to get better at it, and to comprehend more and more as you learn and experience more and more.