[OC-Series] I'm the Last Person Who Remembers the Original Timeline. I Have Four Days. | Chapter 27: The Noise Floor

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The carrier was still up.

That was the first thing I checked, every time the chronometer told me a number I had stopped believing. Sarah's frequency, the carrier I held open on it steady under everything, the return telemetry low and even on the scope. Heart rate slow. Breathing shallow and regular. Cold, all the way down into the part of the body that doesn't know how to lie about being cold. Steady.

She was out there holding still, and I was in here doing the same, and between us was a boundary about eight centimeters off the acrylic and a probe walking the perimeter like a hand feeling along a dark wall for a switch. I read the boundary by ear now. The hull groaned when the water leaned on it, a long low complaint that came a little closer together than it had the last time I bothered to count, and the pitch held, which meant the wall was still the wall and not yet a problem I would have about four seconds to solve.

The fan ground away under the floor. It had a catch in it, a small periodic hitch where the bearing dragged on the graphite I had crushed into it out of a mechanical pencil, and the hitch came around more often than it used to. Every time it caught I waited the half second to find out whether it would keep turning. So far it had kept turning. That was the whole of my luck, accounted for.

I had everything I was going to have. The array was a dead bus. One LEGO sensor on the scrubber line, one rebuilt antenna on the tether, no spare, no solder, no epoxy, nothing to fix anything with if it broke, which meant the entire job had narrowed down to not letting anything break and not doing anything stupid.

So naturally I went looking for the letter.

I want to be precise about how I let that happen, because I watched myself do it.

I had relented on the asking. Sarah was not going to answer the Manifest, I had stopped pushing it, and that was the right call. With the asking off the table there was nothing to do on her line but hold it and keep my readings flat so the channel did not carry my bad afternoon to her end. Holding is not a task. It is the absence of one. And I had a body full of adrenaline with nothing to spend it on and a head that does not do well in an empty room.

The letter was the only unsolved problem in the place. The only voice still trying to say something.

The carrier was still riding the boundary band, broadcast only, no return rhythm, degrading the whole time I had been pointed at Sarah instead of at it. I had pulled the strong terms out once and narrowed back to her frequency and set the rest aside, on the reasonable grounds that reading it cost air and power and attention I could not spend. That had been true. It was still true. I told myself I would only characterize the carrier this time. See how far it had slid, log it properly. Not read it. There is a difference, and I leaned on the difference the way you lean on a railing you already suspect is loose.

I moved the receiver off Sarah's frequency and back onto the boundary band. The transmit side stayed where it was, the open carrier still going out to her, so her line stayed up while I listened somewhere else. What I gave up was the read of her body coming back. The scope went from her steady low telemetry to the boundary band's hiss, and the hiss was most of what was there.

The carrier sat under the noise floor. I could see the place where it should be the way you can see a star you can only catch from the side of your eye, gone the moment you look straight at it.

To pull a buried repeating signal up out of noise you stack the repeats and average them. The noise is random, so it averages toward nothing. The signal repeats, so it reinforces. Stack enough and the thing climbs up out of the hiss into something you can read. It gets expensive fast. Cutting the noise in half costs four times the stacks. One layer deeper than that costs a great deal more than four. Sam Carter would have had it decoded inside a single commercial break, and then explained it to three people who outranked her. I had a single sensor, a degraded antenna, and time that was getting stranger by the hour.

That was the other thing. The hour itself.

The differential was still coming apart, the way Moreau's math said it would as the boundary closed and the mismatch region ate more of the space I was sitting in. My subjective clock and the cesium clock had been five and a half to one when I started keeping track. They were closer now. The number had slid down through five, past four, and was not done sliding, and the slide had a feel to it I do not have a clean word for. Wading. Each step into deeper water, the water pushing back harder, my working-time leaking out faster than the chronometer alone would have told me. The advantage that had been mine, the long hours inside the bubble, was being handed back, and I could feel it being handed back. There was no instrument for that. There did not need to be.

All of which is to say I did not have hours to stack repeats at the noise floor I had. To go deeper I needed a quieter floor. And the loudest thing in my noise floor was the fan.

The fan threw electrical hash from a dying motor and mechanical buzz from a bearing that was already half gone, and the buzz coupled straight into the antenna mount through the frame. Kill the fan and the floor would drop. Kill the fan and the same stack would reach a layer deeper. Kill the fan and the scrubber, which only works when air is moving through it, would stop pulling the room's air across the bed, and the carbon dioxide the fan kept stirred and moving would start to build, and the number on my one sensor would start coming down with it.

I had run that math the night the fan first seized. Killing circulation bought a slow problem, eight to twelve real hours before that became a survival problem, back when my runway was longer. The runway was shorter now. The repair that saved the fan had burned the air doing it, and the ceiling never came back. The slow problem was faster than it used to be, and I did not have the old margin to spend on it.

I looked at the scrubber readout. Low eighties, where my low eighties used to be a healthy number and now was just the top of the box I lived in.

SCRUBBER  82
FAN       ON  (grind, periodic)
RX BAND   boundary  /  SNR below floor
TX        Sarah freq, carrier open

I want it on the record that I knew exactly what I was doing and did it anyway.

I killed the fan.

The grinding stopped, and the module went into the kind of quiet you can hear, the quiet of a thing that is supposed to be making noise and is not. The hull groaned once into it. The noise floor on the scope dropped like a curtain coming down, and the star I could only catch from the side came out where I could look right at it.

I started the stack.

Averaging is patient work and there is nothing to do while it runs but watch the number and breathe air that is slowly getting worse, and notice both. The carrier climbed out of the hiss term by term, the way it had the first time, the strong leading edges arriving first and the high middles still eaten. The opening word was already mine from before. The next line had broken off where I had left it, and now it ran a little further before it died.

The eaten gap in the first real line filled in. One word, where there had been blank.

If you are reading this the line is still open.

I had guessed at that one the first time and refused to write the guess down, which had been correct, because the guess and the truth turned out to be the same word and I still would rather have it from the signal than from my own want. The line was still open. That was the condition the whole message hung from. He was telling me that the fact I could hear him at all meant something, and the something was in the next line, the one that ran which means I have run out of and then died, and that gap had not filled yet. I needed more stacks for it. More stacks meant more time at the lowered floor. More time meant the number.

The number was at seventy-eight.

I let it run. The hull leaned and complained. My head had begun the particular thickness that carbon dioxide brings on, the dull pressure behind the eyes that arrives before you have decided to call it anything, the early edge of a headache and the early edge of not caring that you have one. I knew the symptom. Knowing the symptom is not the same as the symptom going away.

The second gap filled.

which means I have run out of time.

And the two lines closed up into one sentence, his voice from the far side of a boundary, a version of me who grew up in Laval and worked for a company that does not exist in my timeline, talking to the version who grew up on the Plateau, across the only band the two of us ever shared.

If you are reading this the line is still open, which means I have run out of time.

There was more under it. The stack had pulled up a fainter thing from deeper in, below the lines I already had, and it was mostly gone, the way the deep terms always go, the high frequencies stripped off until only the bones are left. I could see it was addressed. I could see one word in it that came up clean because it was the one word in the message the high middles could not hurt, a short hard word that survived everything.

My name. Again. Further down than the first one, riding a line I could not read.

I sat with that. He had written my name into it twice, once at the top to start the thing and once down here where a man stops being careful with a letter and starts saying the part he actually called to say.

And this is the place where I caught myself.

The number was at seventy-four and my head was a slow swamp and I was looking at the eaten span around my own name, the high middle of it gone, three or four syllables of dead air with the bones of a word on either side, and I started to fill it.

I had the shape. I had the rhythm of where the missing piece sat. The brain that was running low on good air wanted to drop a word into that hole so badly, wanted the man on the other end to have finished his sentence. I felt my hand move toward the pad to write the word the gap was the right size for.

I stopped my hand.

That is the one rule. You do not hold a séance with a degraded signal. You read what arrived and leave the holes as holes. They are not a puzzle to solve, they are missing data, and the moment you sketch in missing data you are not reading his letter anymore, you are reading your own in his handwriting. The thing I wanted to write in that gap was a thing I wanted to be there. That is exactly why it could not go in.

I took my hand off the pad. I wrote nothing.

The number was at seventy-three. The air had gone past uncomfortable into something my body was arguing with me about, and the line I had come for was finished and I had nowhere to put the want, so I did the only correct thing left and put the fan back.

I hit the start.

The motor turned a quarter way and the bearing caught hard and it stopped.

I hit it again. Caught. Stopped. The graphite I had packed in there was a temporary lie I had told a permanent problem, and the problem had been waiting to call it, and it was choosing now, with the number at seventy-three and falling and my head full of wet sand. Tabarnak. I hit it a third time and held the contact closed and leaned on the thing with everything I had the way you lean on a stuck valve, willing torque into it through a switch, which does nothing, which I knew did nothing, and the bearing dragged and screamed and then it broke free and the fan turned and kept turning, grinding now in a new and worse register, a sound I had not heard it make before and would be hearing from now on.

Air started to move. The scrubber got its throughput back. The number stopped falling.

I sat in the bad air and waited for the good air to come back, and while I waited I narrowed the receiver off the boundary band and back onto Sarah's frequency, because I needed something to read that was not a dead man, and because I had been off her telemetry for the length of two stacks and a fight with a fan.

Her telemetry came up wrong.

Heart rate high and climbing, breathing pulled short and ragged, the autonomic signature spiked into a shape I had calibrated against her body months ago and had never once seen it throw on purpose. Fear. Real fear, the kind the body does not perform, running up the line in the time I had not been watching it.

Something had happened to her out there while I was in here reading mail.

I did not have a way to ask what. I had the way I always had, which was to be steady, to hold my own readings flat and even and put the shape of a person who is fine onto the bidirectional line so the only thing crossing to her from my end was calm. I brought my breathing down on purpose, slowed it under the headache, made my body lie clean. I held the carrier and I held myself in the shape of nothing-is-wrong and I sent it down the line toward whatever had her, the only thing I had to send, which was the fact of being there and being level.

It took longer than I wanted. The water leaned on the hull and I kept my breathing flat against it. And then her signature started to come down. Heart rate easing off the spike, breath lengthening, the ragged edge smoothing back toward the cold even hold she had carried all night. Whatever it was, it passed, or she put it down. She had always been able to put things down. She went still under fear instead of bolting from it, and for four years I had read that stillness as distance. I had it backward. I worked that out too late to do anything with it.

I did not know what had frightened her. I told myself it was the cold and the dark and the length of the thing, that anyone planted alone at the edge of a field in the middle of the night would spike, and that a steady reference would bring it down. It was a story that fit everything I could see, and I had no reason to reach past it. I had done the one useful thing the room allowed me to do, which was hold still and stay level and let her read it, and it had worked, and I left it there.

The number climbed back toward the low eighties, not all the way, a point short of where it had started, the ceiling lowered again by exactly what the last fan-off had cost. The box I lived in had gotten a little smaller while I was reading. That is the arithmetic of the place. Every answer costs air and the air does not come back to where it was.

Which brought me to the part I have to be honest about.

The lines I had not read were right there. Three of them, the strong leading edges already mine from the first pass, the high middles still eaten, the operative words at the end of each one gone into the noise. I sealed it on purpose. There was no. And then nothing. Already. And then nothing. Do not. And then nothing. The reasons and the warnings, the part a man actually calls to say. One more fan-off pass, one more clean window, and the stack would very likely pull at least one of those words up out of the hiss into the light.

I had the method. I had proven it twice in one sitting. The only thing standing between me and the end of the letter was the cost of running it.

I told myself the cost was the air. The runway was lower now, the fan was worse now, the next restart might be the one where the bearing did not break free, and I could not spend another window without risking the circulation entirely, and a man with no circulation does not get to read anything ever again. All true. Every word of it true. The engineering answer was that I could not afford the next pass, and the engineering answer was correct.

And I watched myself reach for the engineering answer the way you reach for a coat hanging exactly where you need it, and I knew, the way you know a thing you have spent your whole life refusing to look at directly, that I was glad to have it to reach for.

I did not want to read it.

There it was. The fan and the air and the runway were real, and they were also the thing I got to hold up in front of the other thing, which was that some animal part of me did not want the rest of those words to arrive. The same part that read a paper eighteen months ago, a paper by a grieving woman about collapsing the boundary between timelines, and felt the floor tilt, and decided it was probably fine, and filed it under later, and took a rotation six thousand eight hundred feet down partly so that later would never come. That paper ended the world. I know the exact shape of the pattern now. I find the most important document in the room, and I set it down gently, and I tell myself I will get to it, and I am very good at never doing it.

I was doing it again, on purpose, with my eyes open, watching my own hand set the thing aside.

I updated the pad, because if I was going to defer it I was at least going to defer it accurately, and write down exactly what had arrived so that my own memory could not come back later and round the holes into something softer than the holes were.

Elliot.
If you are reading this the line is still open, which means I have run out of time.
I sealed it on purpose. There was no ___
already ___
do not ___
( deeper, faint, mostly eaten: ___ Elliot ___ )
high middles gone. do NOT fill. read what arrives.

Then I narrowed the receiver back to her frequency, and the boundary band dropped out of the window, the dead man's carrier still broadcasting into a space I was no longer pointed at, still degrading, still saying the part I had decided I would get to.

Sarah's telemetry came up steady and even. Heart slow, breath long. Holding.

I held her carrier and sat with the thing I will admit to a log and to no one alive. The only voice in the dark that would actually answer me was a recording of myself dying somewhere I would never reach. The only living person on the line would not say a word. I had just chosen the recording's silence over the woman's, and then chosen not to finish even that. I keyed nothing. The carrier was up. That was enough.

The differential slid another notch toward even, the water a step deeper, my long hours running out under me faster than the chronometer would say. The hull groaned. The groan came a little closer to the one before it, and the pitch held, so the wall was still the wall.

I left the letter where it was, logged and almost legible, one clean window from the end of it. I had the method to finish it, and I had just watched the fan and the number on my one sensor spend most of what was left of my ability to choose when. I set the most important document in the room down one more time. The difference now, the cold-clear thing the bad air had not taken yet, was that I could count how many more times that was going to be, and it was not many.