Marce pulled back out into the full star field. “Now, all of these stars are in the space the Interdependency claims for its own, but not all of them have systems that humans can live in. In fact, of these more than five thousand star systems, only forty-seven of them have humans in them.” He made the star systems of the Interdependency glow more brightly, so the children could see them. The systems were not generally close to each other in space; they seemed randomly distributed, diamonds among grains of sand.

“Why are they all so far apart?” asked one of the children, rather conveniently, for the purposes of the next part of the standard presentation.

“Excellent question!” Marce said. “Now, you might think that all the human systems would be huddled close together so they would be easy to travel to, but all the systems are connected not in space, but by the Flow.”

A bunch of lines arched out of the human systems, connecting them to each other system, prompting another set of appreciative coos from the children.

“The Flow is like a super shortcut through space,” Marce said. “Normally, it would take years or even centuries for humans to get from one star system to the next. Even the closest systems are a few light-years away from each other, and using regular drives, even that relatively short distance would take twenty or thirty years for us to cross. Even our most advanced starships, called ‘tenners,’ can’t make that trip. With the Flow, we can travel between systems in weeks or months at most. But, here’s the catch: We can only travel to the systems where the Flow is nearby.”

He zoomed in to another system, this one with ten planets, and zoomed in further. “Does anyone know which planet this is?” There was no answer. “This is called Hub, and it’s the capital of the Interdependency. Does anyone want to guess why?”

“Because that’s where the emperox lives?”

“Well, yes, but the emperox lives there for a reason, and the reason is this.” Marce tapped his tablet and the planet of Hub was surrounded by what looked like a whirlpool of lines, swirling in the space above the world. “Hub is the one place in the Interdependency where all the Flow streams converge—it’s the only place you can get directly from and to nearly every system in the Interdependency. That makes it the most important planet for trade and travel. If we couldn’t travel through Hub, some systems in the Interdependency would be years away from each other. That’s why the planet is called ‘Hub.’ It’s the center of our universe, so to speak.”

“Can’t we just make a path in the Flow between planets?” This question was from one of the adults, who apparently had gotten so sucked into the presentation that he forgot question time was for the children.