A Journey of Scales

"Did you know the sun's 1,300,000 times bigger than the earth?" my father said to me in a dream. I thought it was real, like a normal day, since he never usually talks about astronomy. In response, I said, "If you think that's amazing, I'll show you the scales with comparisons of everyday objects."

For a moment, I told him to imagine what I was saying.

"If the sun was the size of a basketball," I said, shaping my hands into a ball-form, and then pulling out a bluish marble from my pocket. My father finished the sentence, "Then the earth would be the size of the marble."


"No," I said, "In fact, it would be Jupiter that would be the size of the marble. The earth would be the size of a grain of sand."

Moving on, I said, "Now, if we want to see just how far the planets are from the sun, and not just their sizes, we have to make the scale even larger."

I told him now to imagine that the marble was the size of the sun, the grain the size of Jupiter, moving the scale down by one unit. Setting the Sun-marble in the center of the floor, I stretched my arm until it was three feet from the marble. Setting my imaginary sand-grain there, I said, "That's where the FIRST planet would be, Mercury. The others are still farther. So even though they're extremely small compared to the sun, they're also extremely far away, so they don't become overwhelmed by the sun's energy."

In this situation, sand-grain Jupiter would be some ten feet from the marble, if I remember correctly. The Sun is still hot enough and powerful enough to radiate its heat even across such a distance, spanning many times its own width.

I woke up at this point, disappointing this conversation had only taken place there and not in the waking world. You should visit here if you're interested in learning more about Solar System scales:
http://www.noao.edu/education/peppercorn/pcmain.html

And that's just the Solar System.  The Solar System. That's just the Heliosphere, which is the sphere of our sun's influence; past this tiny shell, which itself is like a grain of sand compared to the nebulae and clusters of our galaxy, lies an entire cosmos filled with progressively larger and larger structure, past the realm of human comprehension.