Greg Egan - The Clockwork Rocket

If the audience was unpersuaded by her message of doom, the attempt that followed by Councilor Eusebio to attract supporters (or even volunteers!) for his Ride Beyond the Sky was greeted by a veritable uproar of disbelief and derision. To anyone willing to back this venture: we have a design for Mechanical Wings gathering dust in our cupboard, awaiting only the life-giving touch of a gullible investor.

In the interests of sanity, Talk consulted Professor Ludovico of Zeugma University, who explained that the Hurtlers bringing such angst to last night’s double act are in fact nothing more than Spontaneous Excitations of the Solar Miasma. Despite its alarming appearance this phenomenon can do no harm to anyone, given that said Miasma is unable to interpenetrate our own plentiful atmosphere.

Ten more nights of this unprecedented madness remain. If the customers were paying then this cheerless and unscrupulous diversion would quickly close for want of funds, but Talk urges the next best outcome: an empty hall, to shame these charlatans into silence.

When Yalda reached the apartment Daria was awake, so she showed her the piece.

“I wouldn’t pay too much attention to Talk ,” Daria said loftily. “Their idea of pushing the intellectual boundaries of journalism is to cover a literary salon.”

“What’s a literary salon?”

“An event where people who can’t read or reason gather to reassure each other of their own importance.”

Yalda said, “But anyone who reads this will think the whole thing’s some kind of… investment scam!”

Daria was amused. “Anyone who’d take this uncomprehending babble seriously was already a lost cause: they were never going to help you improve the Peerless , let alone volunteer for the ride.”

“Maybe not,” Yalda conceded. “But—”

“But you want everyone in Zeugma to understand what’s at stake?” Daria suggested.

“Of course. Don’t you think they’re owed that?”

Daria said, “I’ve been in the business for ten years, and I’ve had notices far worse than this. Believe me, the people who are truly curious will still come.” She rolled the sheet deftly into a cylinder and launched it across the room. “Just forget about it.”

Lidia had worked a late shift and was still asleep; Daria agreed to take the children to school. Yalda did her best to follow Daria’s advice, but when she reached the university Giorgio had more bad news for her: the senior members of the department had voted to refuse Eusebio’s offer to fund a new observatory. What’s more, they were taking their title over the land to Zeugma’s Council, seeking an order forbidding Eusebio from interfering with their present use.

Giorgio said, “If the telescope is raised entirely above the atmosphere it would actually improve the quality of observations. So if you can get the right wording on the order…”

Yalda was in no mood for jokes. “I thought you were going to persuade your friends to vote for this! Whatever they think of Eusebio’s rocket, a bigger telescope would be a worthwhile trade-off, surely.”

“I’m sorry,” he said. “Ludovico had more favors to call in than I did.”

Yalda didn’t doubt that Giorgio had kept his word. But he was still trapped in the kind of anesthetized state from which she’d taken so long to emerge herself. When he argued the physics with her, he accepted that the orthogonal cluster theory of the Hurtlers was as plausible as any alternative—but he still couldn’t bring himself to take the threat seriously, to look at his children and imagine their extinction.

Yalda had a lecture to deliver for the introductory optics course. As her students dutifully recorded her diagrams and equations for the laws of thin lenses, she felt like someone handing out useless trinkets at the edge of a raging wildfire. But she was forbidden from discussing Eusebio’s project during her lessons, or holding recruitment meetings on the campus. If any of these bright young men and women wanted to know the truth about the matter, they’d have to make the effort to turn up for the night’s unscrupulous diversion.

At lunchtime, as Yalda entered the food hall she saw Ludovico coming out of the pantry, his arms laden with loaves for a group of fellow diners. She hung back to avoid crossing his path, but he saw her and approached, calling out to her in a booming voice pitched to attract as much attention as possible.

“Professor Yalda! I’m surprised to see you here! I thought you’d left us for the entertainment business.”

Yalda humored him with a desultory buzz, but couldn’t help adding, “It seems everyone has two jobs these days; I see you’ve gone into journalism, yourself.”

“I was consulted by journalists,” Ludovico replied stiffly. “As a noted authority on the Hurtlers, not a paid employee.”

Yalda said, “Forgive me, but I must have missed all your learned publications on ‘Spontaneous Excitations in the Solar Miasma’. Perhaps you can rectify my ignorance on the topic by explaining precisely what that phrase means?” Everyone in the hall was watching them now, through rear eyes or front.

Ludovico said, “Gladly. One particle of the solar wind expels a fast luxite, which strikes another, prompting it to do the same. And so on. Other, slower light is emitted as well. That is what the Hurtlers are: long chains of activity arising within the gas itself, mediated by fast-moving particles of light.”

Yalda bowed her head in a gesture of gratitude, then feigned deep contemplation for several pauses—contemplation that failed to dispel her puzzlement. “But why are these ‘chains of activity’ parallel to each other? Why are these ‘spontaneous excitations’, these random events, all lined up in exactly the same direction?”

Ludovico replied without hesitation, “A distant source of rapid luxites—not quite at the resonant energy that would trigger an excitation itself—illuminates the solar wind and nudges the particles into alignment. The gas spontaneously emits its own light, but it is not randomly oriented when it does so.”

Yalda was speechless for a moment, marveling at the utter shamelessness of this absurd contrivance. “That’s nonsense,” she said cheerfully. “And you know it’s nonsense.”

Ludovico replied with calm hauteur, “Refute it, then. Show me your meticulous observations establishing my theory’s falsehood.” He began to walk away, but then he paused and turned back to face her. “Oh, I’m sorry, that was thoughtless of me! To make an observation, you might need an observatory … a facility that you’d prefer to see shattered into dust by your demented co-stead. Enjoy your meal, Professor Yalda.”

On stage in the Variety Hall, Yalda tried to push the day’s setbacks out of her mind and focus on the presentation. Even her bountifully bulky body was too small for people to read from the back row, so she’d worked with the Hall’s set designers to create a contraption with a sunstone lamp and lenses that projected a series of printed images onto a large white screen behind her.

As she gazed out into the darkness that concealed the audience, she honed her message, stressing its simplicity. Time was just another direction in space: nothing else could make sense of light’s behavior, or the ferocity of burning fuel. And to keep light tame, time needed to be finite—which meant that history would wrap around and meet itself, as surely as the system of roads and railway lines that wrapped itself around the planet. But while neighboring cities worked together to plan the railway lines between them, any intersections in the histories of worlds would be haphazard and ungoverned. Spectacular as they were, the Hurtlers were mere pedestrian tracks on this map; ahead, there would be busy freight lines.