One of my ongoing fascinations is with sense of scale. Here’s a couple other interesting thought experiments to understand the immensity of our universe:

Suppose that our Earth is the ball in the tip of a ball-point pen. How big would the Sun be, and how far away from the pen tip? First, Hold the ball-point pen up in the air. Now hold a ping-pong ball about 15 feet away from the pen tip. This is approximately a size and distance scale model of the Sun and Earth. The moon would be the size of a dust speck beside the ball in the pen.