"We are standing inside a life-scale model of the Pantheon. Erected in 128 AD by the Roman Empire, it held the record for the world's largest domed building for well over a thousand years. It is still the largest unreinforced solid concrete dome in the world."
Then something very small, practically invisible, buzzed past Keiichi's ear. "Hey, there's a gnat in here, I think."
"Yes. Actually there are 92 of them."
"Why 92?"
"Because a uranium atom has 92 electrons. This is a representation of a uranium atom, specifically uranium-238. It's a simple Bohr model. With 92 protons and 146 neutrons it is the largest stable natural atom in the natural universe, with a half-life of over 4.5 billion years. Anything larger is made artificially in nuclear reactors, nuclear explosions, or as short-lived radioisotopes in supernova blasts."
"I see. So where is it? The atom, I mean?"
"You're standing inside it."
"Huh? You mean this whole huge volume of space is.."
"Yes. This whole space represents a single atom."
"But wait, where's the rest of it?"
"You mean the nucleus?"
"Yeah. I don't see it anywhere."
"It's up there." She pointed. "The center of the atom." They floated upward. "It has a diameter of 15 femtometers, making it larger than any other naturally occurring atomic nucleus. This is as big as it gets. See? It's right over here."
"Where? Past that little marble thing?"
"Keiichi, it is that little marble thing."
He bent over and stared at it. He could barely see it. A bit over a centimeter wide, it was buzzing and jostling around like an angry hive of tiny bees. All 238 of them packed in such a tiny volume.
"That's it? In this whole huge dome?"
"Yes."
"But it's practically empty!"
"Yep."
"So physical matter is basically.. a whole lot of nothing?"
"Yeah, pretty much."
She poked her finger into his shoulder. "When I press my finger into you like that, it is actually the electroweak force that is causing the resistance that is stopping my finger. There is no actual physical contact anywhere, in the sense of particles getting close enough to actually touch. The nuclear forces prevent it. So in a sense I am not actually 'touching' you at all."
"I see."
"Now let's go up to the opposite end of the scale." Everything shifted.
They were now floating in a black expanse. "This is intergalactic space. More specifically, it is the volume of space in-between galactic superclusters. It constitutes over 99% of the volume of the observable universe."
"A whole lot of nuthin'."
"Yep. The universe is appallingly empty, on both scales. The physical structure of the universe is actually very frothy, sort of like soapy suds when you take a bath. The galactic superclusters are all clumped along very thin strips and point junctions that interconnect the frothy soap bubbles."
"And the inside of all those huge soap bubbles.."
".. is empty. As empty as it gets. For a billion light years in every direction."
"More nuthin'."
"Yes. Now let's look at an intermediate scale." Everything shifted again.
"This is a scaled representation of your sun, Sol." Keiichi saw a tiny dot about the size of a period on a printed page. "The nearest neighboring sun would be Alpha Centauri, about 4.24 light-years away, over there." She pointed.
"Where?"
"Let's go see."
They had travelled about 2 kilometers. He asked, "Here?"
"No."
2 kilometers more. "More?" "Uh-huh."
Again. "You're kidding."
This repeated a few more times.
After about 14 kilometers they finally stopped. Another tiny dot the size of a period.
She said, "If your sun was scaled up to 1 foot radius, Alpha Centauri would be over 10,000 miles away."
Keiichi shook his head. "This is nuts. Space is so empty."
"Yes. So let me now ask you, given what you have learned, would you consider a random meteor, a lump of rock, in the great scheme of things, to be something rather special?"
"Yeah."
"Rare?"
"Of course."
"Perhaps even precious?"
"Well, I sort of see what you mean... Anything at all would be pretty special given the complete emptiness surrounding us."
"Good, remember that. Now let's see something even more rare." Another shift.
There were floating next to what looked like a large irregular semi-translucent sphere. Several snake-like entities were heading towards it. "This is the moment of conception. Between 100 million to a half-billion sperm cells are all swimming frantically to find this, the egg. Only one will succeed."
"Heh. So you have better odds of winning the Power Ball lottery jackpot than a sperm has of fertilizing that egg."
"Yes."
"That is one lucky sperm. You know, it seems like all of the interesting things in the universe are rare. Special."
"Yep. All life on Earth exists in a supremely thin layer, thinner than skin of an onion on the same scale. The bulk of the Earth's mass, 99.999..% of it, is dead. See a pattern here?"
"God seems to like rarity."
"Yes."
"But why? Why not simply create a universe that is completely alive? Make everything living? Why is it all so empty, so dead?"
"Keiichi, that is a very good question. I wish I had an answer for you, but I don't. My personal theory is that it is because it makes those very few things in the vastness of the universe even more precious, even more special..."
Thanks. That was a good read.