46: A-LINE.

June 2070 Since coming through the A-line we arent alone with Q any more, Mum. Theres a regular flotilla escorting the thing now, like a navy flag day, all the rock miners and bubble-dwellers coming out to see the beast as it passes. Its kind of strange for us. After a cruise of fourteen months, weve got all this company. But they dont know were here. The Liberator is staying inside her stealth shroud, and there are a couple other navy tubs out here, keeping the sight-seers at a good distance and coordinating the latest assault on Q...

Bella, Thales said softly.

Pause. Ednas talking head froze, a tiny holographic bust suspended over the surface of Bellas desk. Cant it wait, Thales?

Cassie Duflot is here.

Oh, crap. Wife of dead hero space-worker, and professional pain in the backside.

You did ask me to inform you as soon as she arrived.

I did.

The message from Edna was still coming in. Bella was a mother as well as a politician; she had rights too. Ask her to wait.

Of course, Bella.

And Thales, while shes waiting, dont let her mail, record, comment, blog, explore, analyze, or speculate. Give her coffee and distract her.

I understand, Bella. Incidentally Yes?

Its little more than an hour to the principal strike. The Big Whack. Or rather until the report reaches us.

She didnt need reminding of that. The Big Whack, mankinds last hope against the Q-bomband perhaps the end of her daughters life. Okay, Thales, thank you, Im on it. Resume.

Ednas frozen image came alive again.

Ednas voice, having spent twenty-four minutes crawling across the plane of the solar system, sounded strongly in Bellas Mount Weather office. And Thales smoothly produced pictures to match the words, images captured by a variety of ships and monitors.

There was the Q-bomb, a ghostly droplet of smeared starlight, hovering over Bellas desk. It was passing through the asteroid belt right nowthe navys A-lineand she was shown a distant sprinkling of rocks, magnified and brightened for her benefit. There was something awesome about the image; six years almost to the day since the object had first been spotted swimming past Saturns moons, here it was among the asteroids, home to a branch of mankind. The Q-bomb was here, in human space. And in just six more monthsat Christmas time in this year of 2070the Q-bomb was destined to make its rendezvous with Earth itself.

But the bombs passage through the belt gave one more chance for an assault.

Edna was talking about the attempts so far. Thales showed images of nuclear weapons blossoming against the bombs impassive surface, and ships, manned and robotic, deploying energy weapons, particle beams, and lasers, even a stream of rocks thrown from a major asteroid fitted with a mass driver, an electromagnetic catapult.

Pea shooters against an elephant, Edna commented. Except it isnt quite. Every time we hit that thing it loses a little mass-energy, a loss in proportion to what we throw at it. Just a flea-bite each time, but its non-zero. Lyla Neal has been doing some modeling of this; Professor Carel will brief you. In fact we hope one outcome of the Big Whack, assuming we dont knock the thing off its rails altogether, is to confirm Lylas modeling, with a data point orders of magnitude away from what weve been able to deploy so far. Anyhow well find out soon.

As for the cannonball, the tractor is doing its job so far. All systems are nominal, and the cannonballs deflection is matching the predictions... In her quiet, professional voice, Edna summarized the status of the weapon.

When she was done, she smiled. Despite her peaked cap, she looked heartbreakingly young.

Im doing fine in myself. After more than a year aboard this tub I need some fresh air, or fresher anyhow. And under a dictionary definition of stir crazy you could write down John Metternes. But at least we havent killed each other yet. And if you look at this cruise as an extended shakedown of the Liberator shes performed fine. I think we have a good new technology here, Mum. Not that thats much consolation if we fail to deflect Q, I guess; well all be in deep yogurt then.

The other crews are doing fine too. I guess this is an operational test for the navy itself. A few veterans of the old wet navy say they feel out of place on board ships where even the rawest nugget has passed out of the USNPG. That was the U.S. Naval Post Graduate School in Monterey. Right now, while were waiting for the drama to begin, theres a sort of open-loop church service going on. Those who choose to are saying their prayers to Our Lady of Loreto, the patron saint of aviators.

As for the Spacers, they are cooperating, mostly, with the cordon and other measures. But were ready to take whatever action you see fit for us to take, Mum.

Sixty minutes to showtime. Ill speak to you after the Whack, Mum. Love you. Liberator out.

Bella had time for only a short reply, for it would reach Edna with only minutes left before the strike. I love you too, she said. And I know youll do your duty, as you always do. She was horribly aware that these might be the last words she ever spoke to Edna, and that in the next hour she might lose her only daughter, as poor, angry Cassie Duflot, waiting outside, had already lost her husband. But she could think of nothing else to add. Bella out. Thales, close this down.

The holographic display popped out of existence, leaving a bare desk, with only a chronometer counting down to the time of the Big Whack assault, and the still more important moment when news of it would reach the Earth. Bella composed herself. Show Cassie in.

Somehow Bella had expected Cassie Duflot to show up in black, as when Bella had last met her when she had handed over her husbands Tooke medal: still in widows weeds, after all this time. But Cassie wore a suit of a bright lilac color, attractive and practical. And nor, Bella reminded herself, was Cassie going to be sunk in grief as she had been during that visit. It would be easy to underestimate her.

Its good of you to see me, Cassie said formally, shaking Bellas hand.

Im not sure if I had much choice, Bella said. Youve been making quite a splash since we last met.

Cassie smiled, a cold expression almost like a politicians. I didnt mean to make any kind of splash, or to cause anybody any trouble. All I am is the widow of a navy engineer, who started asking questions about how and why her husband had died.

And you didnt get good enough answers, right? Coffee?

Bella went to the percolator herself. She used the interval to size up her opponent, for that was how she had to think of Cassie Duflot.

Cassie was a young woman, and a young mother, and a widow; that gave her an immediately sympathetic angle to snag the publics attention. But Cassie also worked in the public relations department of Thule, Inc., one of the worlds great eco-conservation agencies, specializing in post-sunstorm reconstruction in the Canadian Arctic. Not only that, her mother-in-law, Phillippa, had moved in senior circles in London before the sunstorm, and had no doubt kept up a web of contacts since. Cassie knew how to use the media.

Cassie Duflot looked strong. Not neurotic, or resentful, or bitter. She wasnt after any kind of revenge for her husbands death or for the disruption of her life, Bella saw immediately. She was after something deeper, and more satisfying. The truth, perhaps. And that made her more formidable still.

Bella gave Cassie her coffee and sat down. Questions with no answers, she prompted.

Yes. Look, Chair Fingal Call me Bella.

Cassie said she had known a little of her husbands activities in his last years. He had been a space engineer; Cassie knew he was working on a secret program, and roughly where he was stationed.

And thats all, she said. While James was alive that was all I wanted to know. I accepted the need for security. Were at war, and during wartime you keep your mouth shut. But after he died, and after the funeral and the ceremonialsyou were kind enough to visit us Bella nodded. You started to ask your questions.

I didnt want much, Cassie said. She was twisting the wedding ring on her finger, self-conscious now. I didnt want to endanger anybody, least of all Jamess friends. I just wanted to know something of how he died, so that one day the children, when they ask about himyou know.

Im a mother myself. In fact, a grandmother. Yes, I do know.

It seemed the navy had badly mishandled queries that had initially been valid and quite innocent. They stonewalled me. One by one, the navys liaison officers and the counselors stopped returning my calls. Even Jamess friends drew away. This blank shutting-out had, quite predictably, incensed Cassie. She had consulted her mother, and had begun her own digging.

And she had started drafting queries for Thales.

I think because Thales exists, whispering in the ear of anybody on the planet who asks him a question, people believe that our society is free and open. In fact Thales is just as much an instrument of government control as any other outlet. Isnt that true?

Bella said, Go on.

But I found out there are ways even to get information out of an AIs nonanswers as well as its answers. She had become something of a self-taught expert on the analysis of an AI traumatized by being ordered to lie. She produced a softscreen from her bag and spread it over the desk. It showed a schematic of a network laid out in gold thread, with sections cordoned off by severe red lines. You cant just dig a memory out of an AI without leaving a hole. Everything is interconnected Bella cut her off. Thats enough. Look, Cassie. Others have asked the same sort of questions before. Its just that you, being who you are, have become more prominent than most.

And where are those others? Locked away somewhere?

In fact some were, in a detention center in the Sea of Moscow, on the far side of the Moon. It was Bellas own darkest secret. She said, Not all of them.

Cassie took back her softscreen and leaned forward, her face intent. Im not intimidated by you, she said softly.

Im sure youre not. But, Cassiesit back. The office has various features designed to respond to any threat made against me. Theyre not always very clever at decoding body language.

Cassie complied, but she kept her eyes fixed on Bella. Space-based weapons systems, she said. Thats what my husband was working on, wasnt it?

And she spoke of hints from the sky, traces, fragmentary clues that had been assembled by conspiracy theorists and sky-watchers of varying degrees of sanity and paranoia. They had seen the straight-line exhaust trail of a ship sliding across the sky at impossible speeds. The Liberator, of course. And they had seen another vessel, slow, ponderous, massive, moving in the asteroid belt, leaving behind the same kind of trail. That was clearly the tractor, preparing for the Big Whack. These ships had all been shrouded, but mankinds invisibility shields were not yet perfect.

Bella asked, So what do you think all this means?

That something is coming, Cassie said. Another sunstorm, perhaps. And the governments are preparing to flee with their families, in a new generation of superfast ships. Thats not a consensus view, but a common suspicion, Id say.

Bella was shocked. Do people really think so little of their governments that they imagine were capable of that?

They dont know. Thats the trouble, Bella. We live in the aftermath of the sunstorm. Maybe its rational to be paranoid. Cassie folded away her softscreen. Bella, I have followed this path not for my husbands sake, or my own, but for my children. I think you are hiding somethingsomething monstrous, that might affect their future. And they have a right to know what that is. You have no right to keep it from them.

Time for Bella to make her judgment about what to do about this woman. Well, Cassie was not a criminal. She was in fact the sort of person Bella had been appointed to protect.

Look, Cassie, Bella said. Youve picked up some of the pieces of the jigsaw. But youre assembling them into the wrong picture. I dont want any harm to come to you, but on the other hand, I dont want you to do any harm either. And by spreading this sort of theory around, harm is what you may inflict. So Im going to take you into my confidencethe confidence of the Council. And when you know what I know, you can use your own judgment on how best to use the information. Is that a deal?

Cassie thought it over. Yes, Bella, thats fair. And she looked at Bella, apprehensive, excited. Scared.

Bella glanced at the clock on the wall. Thirty minutes before she would receive news of what had become of the Big Whack experiment. That desperate drama must be playing itself at this very moment, out among the asteroids, twenty-eight light-minutes away.

She put that aside. Lets start with the Liberator, she said. Your husbands legacy. Graphics, please, Thales.

They spoke of the Liberator. And of the Q-bomb it had been shadowing for months. And then Bella showed Cassie Bob Paxtons last option.

Its just another asteroid, drifting through the belt, Bella said. It has a number in our catalogs, and whoever landed that mining survey probe on itit was a metallic spark on the asteroids coal-dust surfaceprobably gave it a name. We just call it the cannonball. And here is the ship whose exhaust your conspiracy-theorists saw.

I wish you wouldnt call them that, Cassie murmured. She leaned forward to see. It looks like another asteroid, she said. A rock with a silver net around it.

That was pretty much what the tractor was: a minor asteroid, much smaller than the flying-mountain cannonball. The rock had had a net of tough nanotube rope cast around it, and an antimatter-drive engine was fixed to its surface. We used one of the early prototype engines from the Trojan shipyards. Not human-rated but its pretty reliable.

Cassie began to see it. Youre using this to steer the bigger asteroid, the cannonball.

Yeswith gravity. It turns out to be surprisingly hard to deflect an asteroid...

Turning aside the path of an asteroid had been studied for a century or more, since it had become understood that some asteroids crossed the path of the Earth, and, at statistically predictable intervals, collided with the planet.

A dangerous rock was generally too big to destroy. An obvious idea was to knock it aside, perhaps with nuclear weapons. Or you could attach a drive to it and just push it. Or you could attach a solar sail to it, or even paint it silver or wrap it in foil, so the pressure of sunlight pushed it aside. Such methods would deliver only a small acceleration, but if you could catch the rock early enough you might do just enough to keep the rock from hitting its undesired target.

As the asteroid belt was gradually colonized, all these methods had been tried; all failed, to varying degrees. The trouble was that many larger asteroids werent solid bodies at all, but swarms of smaller rocks, only loosely bound by gravityand they were generally rotating too. Try to push them, or blow them up, and they would just fragment into a cloud of smaller impactors that would be almost as lethal and all but impossible to deal with.

So the idea of the gravitational tractor was developed. Position another rock near your big problem asteroid. Push the second rock aside, gently. And its gravity field would tug at its larger sibling.

You see the idea, Bella said. You have to keep pushing your rock just too feebly to be able to escape the asteroids gravity field, so your tractor remains bound to the target. And the target will be drawn away no matter how broken-up it is. The only tricky part is orienting your tractors exhaust plume so it doesnt impact the targets surface.

Cassie nodded, a little impatiently. I get the idea. Youre deflecting the orbit of this rock, this cannonball So that it hits the Q-bomb. The bomb and the cannonball are on radically different trajectories; the impact will be fasthigh-energy.

When will this happen?

In fact, Thales said gently, it did happen, nearly half an hour ago. Two minutes until the report comes in, Bella.

The graphics of tractor and cannonball vanished, to be replaced by a steady image of the Q-bomb, that eerie sphere visible only by reflected starlight, floating in a cloud of velvet above Bellas desk. And beside it was a matchstick spacecraft.

Cassie understood. It took her a few seconds to compose herself. Then, wide-eyed, she said, Its happening now. This impact. And your daughter is out there, in her shrouded battleship, observing. You brought me in at a time like this?

Bella found her voice was tight. Well, I need to keep busy. And besidesI think I needed to see your reaction.

Thirty seconds, Bella.

Thank you, Thales. You see, Cassie No. Dont say any more. Impulsively Cassie leaned across the table and grabbed Bellas hand. Bella hung onto it hard.

In the graphic, bomb and escort hung silently in space, like ornaments.

Something came flying into the desktop image from the left-hand side. Just a blur, a gray-white streak, too fast to make out any details. The impact brought a flash that filled the virtual tank with light.

Then the projection fritzed and disappeared.

Bellas desk delivered scrolling status reports and talking heads, all reporting aspects of the impact. And there were calls from across Earth and the Spacer colonies, demanding to know what was going on in the belt; the explosion had been bright enough to be seen with the naked eye in the night skies of Earth, as well as across much of the rest of the system.

By pointing, Bella picked out two heads: Edna, and then Bob Paxton.

...Just to repeat, Mum, Im fine, the ships fine, we stood off sufficiently to evade the debris field. Quite a sight, all that white-hot rock flying off on dead straight lines! We got good data. It looks as if Lylas projections on the likely loss of mass-energy by the Q-bomb have been borne out. But Bella flicked to Bob Paxton; his face ballooned before her, ruddy, angry. Madam Chair, we havent touched the damn thing. Oh, we bled off a bit of mass-energy, even the Q couldnt eat a fucking asteroid without burping, but not enough to make a bit of difference when that thing gets to Earth. And get here it will. Its not been deflected at all, not a hairsbreadth. It defies everything we know about inertia and momentum.

Andokay, here it comes. We got the numbers now to do some extrapolating about what happens to the Earth if the Q-bomb hits, on the basis of how the rocks we have been throwing seemed to have drained the bomb. Umm. The bomb is not infinite. But its big. The bomb is big enough to destroy Mars, say. It wont shatter Earth. But it will deliver about as large an impact as the planet could sustain without breaking up. It will leave us with a crater the size of Earths own radius. He read, This will be the most devastating event since the mantle-stripping impact that led to the formation of the Moon... He ran down, and just stared at the numbers off camera. I guess thats that, Madam Chair. We did our best.

Bella had Thales hush his voice. Well, there you are, Cassie. Now you know everything. Youve seen everything.

Cassie thought it over. Im glad your daughter is okay.

Thank you. But the strike failed. She spread her hands. So what do you think I should do now?

Cassie considered. Everybody saw that collision, on Earth and beyond it. They know something just happened. The question is, what do you tell them?

The truth? That the world is going to end by Christmas Day? She laughed, and wasnt sure why. Bob Paxton would say, what about panic?

People have faced tough times before, Cassie said. Generally they come through.

Mass hysteria is a recognized phenomenon, Cassie. Documented since the Middle Ages, when you have severe social trauma, and a breakdown of trust in governments. Its a significant part of my job to ensure that doesnt happen. And youve already told me the governments I work for arent trusted.

Okay. You know your job. But people will have preparations to make. Family. If they know.

Of course that was true. Looking at Cassies set, determined face, the face of a woman with children of her own under threat, Bella thought she could use this woman at her side in the days and weeks to come. A voice of sanity, amid the ranting and the angry.

And somebody was ranting at her right now. She glanced down to see the choleric face of Bob Paxton, yelling to get her attention. Reluctantly she turned up the volume.

We got one option left, Chair. Maybe we ought to exhaust that, before we start handing out the suicide pills.

Bisesa Dutt.