It had been a couple of years since the Moonseed made the mantle so hot that plate tectonics effectively stopped. The plates were too hot to behave in the rigid way they used to; and the rock of the mantle was just too runny to support big horizontal movements.
It had been thought that would reduce the volcanism for a time, but it didn’t turn out that way.
Still, the map of Earth was recognizable. Just.
The ocean plates were softening and melting back. The continents showed up in his images as black and dark islands in glowing oceans, the ancient granite cratons surrounded by crumpled greenstone. The cratons were the cores around which the continents had accreted in the first place, crust slabs which had formed in the centre of ancient mantle convection cells; now they were being uncovered once more.
It was as if, Henry thought, someone was winding back Earth’s evolution.
And there were giant mantle plumes breaking out all over the planet, flood lavas, volcanic domes, cones and even coronae — features never seen on Earth before, only on lost Venus, basaltic domes surrounded by annuli of ridges and grooves. Nowhere was left untouched in the catastrophic resurfacing of the planet.
Hardly anything of the works of humanity survived.
There was one consolation, though. For a time, Earth was the youngest place in the Solar System.
…I want to tell you how much I admire you people up there. My God, you guys think big. Your schemes to bring in comets to graze the Moon’s atmosphere and increase the volatile content. Rebuilding the crater walls and lunar mountains that are already getting eroded by the rain. No plate tectonics on the Moon, to maintain the carbon and oxygen cycles: so you’ll bake the silicate rocks into glass, drive out the carbon dioxide that’s weathered there, and reverse the erosion… Jesus.
I’m not sure if I agree with your projections that you can reduce the time to true terraforming to a thousand years, but I haven’t had the time to run the math. I don’t think you ought to concern yourself with the objections of the Siberians who have colonized farside. They aren’t even human; let them build their own damn world.
But you talk about using the extremal black holes from the Earth’s debris to tip the Moon, to give it seasons, then to spin it up. It’s a nice idea. A final gift from the Earth, to its daughter…
But, Nadezhda, I have to counsel caution. Are you guys sure you know what you’re doing? You’re going to have sixty-feet tides in those new lunar oceans of yours —
Shit.
Sorry. That was a surface wave, a big one. I think it will be over soon…
The continental cores, the ancient cratons, had resisted the magma plumes for billions of years, and, like knots in wood, were tough to crack. But they were not indestructible.
Even as he watched he could see the last of the African plate — cracking and dissolving like scum — there it went…
Africa had been the oldest continent, most of it formed more than two and a half billion years earlier, surviving for geological ages as the hard, protected core of Pangaea, the world continent. Now it was gone, just a puddle of magma.
Goodbye, Africa. Birth place of man. My God.
And now, where Africa used to be, another huge magma plume was starting. It looked like a solar flare. A fountain of rock blasting straight up, uncurling with perceptible speed…
No, not a fountain. More like a fist, punching out of a sack. A mass the size of a small moon, thrusting out of the Earth.
Henry couldn’t begin to compute the energy behind events like that.
The end must be close now.
Already there had to be significant mixing between the core and the mantle layers. The planet as a whole used to spin at a different speed from its core… Now the whole globe was coupled, structurally. It must be tearing itself apart, like an unregulated motor.
Another pressure wave swept beneath his bunker, cracking the floor. Maybe that was the aftershock of the Africa plume.
He kept to his feet, though.
Now another plate was gone, after five billion years just crumbling away like sugar in water. He thought that was Indo-Australia — the planet was such a mess now it was hard to be sure — and the other plates were starting to slide and crack.
…I know you think I’m crazy to have stayed. I know your new generation of Arks, skimming down from the Moon, had the capacity to take off almost everybody who was left. I know you think I’m like the crazy old fucker who wouldn’t get out of his house when they want to build the highway through it.
Sorry. I guess you don’t know what I’m talking about.
I just didn’t want to leave, is the top and bottom of it. This is my home: here, on the shitty side of the Bottleneck. On the other side is the future, all of the universe, waiting for you.
What would I do on the Moon, except bitch about the processed algae and yack about the old days?
This is my home.
Listen to me. Don’t tip the Moon. Harness the black hole wind. Use it for what it was meant for.
Get out of here, go to the stars.
Godspeed to all of you.
There was more bare magma ocean than continent left now. Giant plumes, everywhere, more of those fists punching out to space—
And here came another shock wave, slamming into the bunker.
An instant of confusion, pain, extreme noise.
He was on his back.
The force field had held. But the whole bunker was over on its side, the floor and walls cracked, shattered to powder.
It felt as if he had bust a leg, a couple of ribs. He couldn’t move. He couldn’t hear anything.
He didn’t suppose it mattered. He was lucky to have survived so long.
The force field was tough. Maybe it would come sailing out of the final destruction event with his old bones preserved inside, battered and crushed.
One monitor was still working, by some miracle. He could still see the Earth.
The planet was a ball of red-brown light, an ocean of magma, barely differentiated, just a few scraps of continent, patches of black slag. But now there were spreading pools of white light at the rims of the magmatic convection cells: plasma, presumably, from the high-energy stuff going on in the interior.
Just like Burnet said. This is the fire. And soon we will merge with God.
The planet looked lopsided. Here came the biggest plume yet, poking out of the equator, where the Pacific plate used to be.
The limb of the planet was… lumpy. Jets of rock vapour pushing out of the lumps, into space. Some of the lumps were falling back, creating craters hundreds of miles across, spectacular impact basins that weren’t going to last more than minutes. And now, a new upswelling—
Shit. You can’t call that a plume. The core must be splitting.
Oh. I’m rising. Like an elevator. The continent must have split. Jane, I think —