imagining. Five hundred metres was a long way to fall. She remembered Caillebot’s reaction when she’d outlined the plan: That doesn’t look survivable.
Maybe he’d been right all along.
Now the tilt was increasing faster. Forty degrees, then forty-five. Thalia’s arms felt as if they were being wrenched out of their sockets, but it was only the effect of her bodyweight so far. When the sphere started rolling, it was going to get much worse. Fifty degrees. The lower extremity of the stalk was beginning to come into view through the windows. In one brief glimpse she knew she’d been right about the war machines. They covered it like a black mould, reaching as high up the shaft as it was possible to see. They must have been very close to the sphere itself.
Something gave way. Thalia felt the sphere drop several metres, as if the upper part of the stalk had crumbled or subsided under the changing load. And then suddenly they were rolling, pitching down the side of the stalk, the angle of tilt exceeding ninety degrees and then continuing to climb. The sphere shook and roared. There was no time to analyse the situation, or even judge how far down the stalk they had rolled. There was only room in Thalia’s head for a single, simple thought: Its working… so far.
She felt a momentary increase in the forces tugging at her body and judged that the sphere had reached the base of the stalk and changed its direction of roll from the vertical to the horizontal. She tried to time the duration of each roll, hoping to judge the distance they had travelled and detect some evidence that the sphere was slowing. But it was hopeless trying to concentrate on such matters.
“I think,” she heard Caillebot call out, between grunts of discomfort, “that we’ve cleared the perimeter.”
“Really?” Thalia called back, raising her voice above the juggernaut rumble of their progress.
“We’re still rolling pretty fast. I hope we don’t just bounce right over the window band.”
It was a possibility neither Thalia nor Parnasse had considered. They’d guessed that the sphere would have enough momentum to reach the edge of the band, but they had never thought about it moving so fast that it would skim right across, moving too quickly to stress the window enough to break. Now Thalia realised that they were open to the awful possibility that the sphere might traverse the entire window band and come to a rolling halt on the next stretch of solid ground.
“Can you see the band yet?” she asked.
“Yes,” called out Meriel Redon.
“I think I can. But something’s wrong.”
“We’re coming in too fast?”
“Not that. Shouldn’t we be rolling in a straight line?”
“Yes,” Thalia said.
“Aren’t we?”
“We seem to be curving. I can see the window band, but we’re approaching it obliquely.”
Thalia was confused and worried. They’d always assumed that the sphere would follow a straight course once it reached the base of the stalk, with only minor deviations caused by obstacles and friction. But now that she concentrated on the tumbling landscape and tried to make out the grey line that marked the edge of the window band, she knew that Redon was right. They were clearly off-course, at far too sharp an angle to be explained by the sphere crashing through the remains of the campus grounds.
“I don’t understand,” she said.
“We went over this. It should be a straight roll all the way to the window band.”
“We’re still going to hit the window band,” Cuthbertson said, his voice reduced to a strangled approximation of itself.
“You’ve just forgotten about Coriolis force.”
“We should be moving in a straight line,” Thalia said.
“We are. But the habitat’s rotating, and it’s trying to get us to follow a helical trajectory instead. It’s all about reference frames, Prefect.”
“Coriolis force,” Thalia said.
“Shit. After everything they taught me in Panoply, I forgot about Coriolis force. We’re not on a planet. We’re inside a fucking spinning tube.”
She’d become aware that the rate of roll was diminishing, the landscape cartwheeling around at half the speed from when they had begun the journey. She could begin to pick out details, landmarks that the Aubusson citizens had already noted.
“We’ll be okay,” Cuthbertson said.
“We’re just going to hit a different part of the window band than we were expecting.”
“Will that make any difference?” she asked.
“Don’t think so. We should break through as easily there as anywhere else.”
“Any second now,” Meriel Redon said.
“We’re coming up on the band. Get ready, everyone. There’s going to be a jolt when we hit the edge of the land strip.”
Thalia braced herself, in so far as bracing was possible when she was already bound like a sacrificial offering. She felt a moment of giddy vertigo as the sphere rolled over the edge of the landscape strip and crashed down onto the vast glassy plain of the window band. The ride became eerily smooth as they trundled over the geometrically perfect surface. With little friction save air resistance, the rate of roll was holding more or less steady.
“Break,” Thalia whispered.
“Please break. And please let us be airtight when it happens.”
Dreyfus knocked on the door to the tactical room before stepping through. A certain deference was advisable. Dreyfus knew that his Pangolin clearance put him on a level footing with the seniors in some respects, but he saw no point in rubbing salt into that particular wound.
“Dreyfus,” Baudry said, breaking off from whatever discussion she’d been having with the other seniors.
“I’m afraid you’re too late. You’ve just missed the demise of the Persistent Vegetative State.”
Without sitting down, Dreyfus moved to a position close to the Solid Orrery. The number of red lights hadn’t changed since last time he’d seen it, but he could draw no consolation from that, knowing what it had cost just to slow Aurora’s advance.
“How many’d we get out?”
“One hundred and seventeen thousand, out of a total population of one hundred and thirty. Not bad, all
things considered, especially as we were basically dealing with corpses.”
“We’ve now concentrated our evacuation efforts on the targets we think Aurora will go for next,”. Clearmountain said.
“Our monitors show that the weevil flows are already changing direction, now they know the Spindle and the PVS are out of the picture.”
“You mean ’nuked’,” Dreyfus said.
“Whatever. So far, though, we can’t say where the flows are most likely to hit next. There are a number of possible candidates. Unfortunately, none of them are habitats where we’ve already started evacuating. We’re starting from scratch.”
“Where are the evacuees going?”
He could tell from their reactions that his question wasn’t a popular one.
“In an ideal world, we’d ship them far across the Glitter Band, well beyond Aurora’s expansion front,” Clearmountain said.
“But even with the high-burn liners, that would involve an unacceptable round-trip delay. Our only practical strategy has been to move the citizens to relatively close habitats, so that the turnaround time can be minimised.”
“Go on.”
Clearmountain cast a glance at the other seniors.
“Unfortunately, Aurora’s projected front is now beginning to impinge on some of the habs where we’ve been moving people.”
“I see.”
“Which means that when we start evacuating those habs, we’re also going to have to shift the recent refugees. With our current resources the situation is borderline containable, but as the front expands, and the
