The End of Eden (Water Worlds 1)

Chapter 5

"Near the edge of our Solar System," Father continued, "fifty times farther out than from here to the Sun, is the Kuiper Belt. Sort of like the asteroid belt..."

"Between Mars and Jupiter?" I asked, instantly ashamed that I finished Father's sentence.

But Father was pleased. "Yes! The Kuiper Belt is like the asteroid belt between Mars and Jupiter, but much, much larger. And it lies in a very stable place at the Outer Edges, where the debris left over from the birth of the Solar System has had time to settle. Now, our destination is the Kuiper Cliff, a drop-off of icy rocks in the Kuiper Belt where the really big, really pure ice planetesimals reside. Once it arrives, a craft like this would sniff out an ice ball of just the right size —perhaps half the size of the Moon, or so — and with an Earth-like ratio of heavy to light water. Likely there will be some methane and ammonia, also various trace elements. I have designed a very nice sniffer for them," he said, and he tapped the side of his nose and smiled.

I smiled back, pretending to understand it all and hoping he wouldn't notice. I didn't want to seem slow and disappoint him. I was just a child, after all.

"Once in position, gravity will begin its magic. The tug effect is small but quantifiable and completely predictable. The craft will be designed with just enough mass to nudge the ice worlds, ever so slowly, ever so precisely, always correcting for error, into a trajectory that will bring them to the inner Solar System. Specifically the two planets most suitable for terraforming, Venus and Mars. It would take vast time, and would need a dependable artificial intelligence to do the aiming."

"Artificial intelligence, Father?"

"Smart driver. Like in your Hundred Clicker. It's sort of my special interest."

Right, I thought, dredging up a memory. I think he mentioned that once before.

"I had calculated that it would take a little over one thousand years for the first ice world to enter the inner Solar System, and I designed its approach to strike Venus a glancing blow, just enough to get that slowly spinning planet moving again in a reasonable orbital rotation."

He pointed to the simulation, and I glanced over just in time to see a close up of a flaming snowball smash into the side of a giant tan-and-gray striped marble, hanging in deep black emptiness. Fireworks spurted from its side as much of the planet tore away, escaping gravity, only to be recaptured in an oblong orbit.

"The impact ejecta plume would coalesce rather quickly. In little over one hundred years, the force of gravity would shape it into an Earth-like moon, but much smaller."

A red hot ring, with a big lump on one side, formed around Venus in the display. The lump was spinning and swallowing up the glowing embers. And, with every orbit in the high speed simulation, it slowed and darkened.

"This new moonlet should stabilize Venus's backward spin — did you know Venus spins backwards? — and the injection of such a mass of water ice should interrupt the greenhouse effect, allowing Earth-like conditions to begin forming within another few hundred years. According to my best trajectories, in as little as a thousand or fifteen hundred years time, Venus would be habitable to humans."

Father waved at the wall and the circles widened a bit. A new path appeared.

"Another ice planet could be aimed at Mars. But its trajectory would be designed to enter the Martian atmosphere on a more direct approach, breaching the mantle and re-igniting that planet's near-dead core."

A vast explosion rocked the red world in Father's simulation. A jet of hot rock and lava shot straight up, like the spurting geysers of Hailuo Valley, but far, far greater.