[ECHO ARCHIVE · LAYER 1 · 71.4% DECODED · KEY: NONE (CARRYING OVER THE SATELLITE TV ERROR-CORRECTION CODE)]
What Layer 1 gave us came to 4.2 seconds in all.
At 25 frames, interlaced, two fields per frame: 105 frames. Sixty-one of them were snow—standard Gaussian noise, a histogram matching any television with no antenna connected. The valid picture was 44 frames, all at the end. From frame 62 the noise drew back from the lower right corner of the picture, drawing back neatly, like someone peeling a sheet of paper up from below. Frames 92 through 105 were the clearest: the left half of an anchor desk, a length of one hand, a station ID at the edge of the desk, and the lower rim of the big screen behind it.
We split the 44 frames into 88 fields, saved each field as a tif, numbered A-001 through A-088. Tong wrote "forensics" on the whiteboard and drew three columns under it: astronomy, text, coding. He capped the pen when he finished and said nobody was to cross columns.
Lao Song took the astronomy column.
Frozen on the big screen behind the desk was a photograph: the sun eclipsed over more than half, the notch toward the lower left; in the foreground a row of transmission towers, four of them, evenly spaced across the frame. Lao Song blew field A-081 up to 400 percent and measured it with a pixel ruler for two days. He doesn't measure with software. He takes screenshots, prints them, and measures the printouts lying over the desk with a thirty-centimeter plastic ruler—he says it keeps the feel of the numbers in his hand.
On day three he posted his results. Eclipse magnitude between 0.86 and 0.89; take 0.87. The curvature of the eclipsed limb back-solves to the moon's apparent radius, with wide error bars. Solar center about 21.5 degrees above the horizon. The moon's azimuth, fixed by the direction of the notch, plus or minus 4 degrees. The towers run roughly east, trending north.
"All this pins down exactly one thing," he said. "The photograph was taken on Earth, at a latitude somewhere in the twenties to thirties north."
"And then?"
"Then I went through every eclipse in the canon." A sheaf of printouts sat weighted at his elbow, corners curled. "From this year to 2100: central-eclipse tracks crossing that latitude band, local afternoon, magnitude between 0.85 and 0.89—two, in all. April 10, 2079, an annular eclipse. March 2, 2116, a partial."
Adebayo asked from behind: "Which is the closer fit?"
"The 2079 one matches on all three items. The 2116 one is off by 1.7 degrees in solar altitude." Lao Song paused. "1.7 degrees isn't much. But I measured four times, and four times it was 1.7 degrees off."
On the fourth day he found a second, independent road. The four towers cast shadows; in the frame only the last stub of each shadow survives, lying across a road shoulder. Assuming standard thirty-five-meter single-circuit tangent towers, and back-solving the solar altitude from the shadow-to-height ratio, he got 20.8 degrees.
"0.7 off from the earlier 21.5," he said. "Each road has its own defects. Taken together, the 2116 eclipse gets harder to defend."
"You still haven't killed that 1.7 degrees."
"I haven't killed it," Lao Song said. "I've turned one line into two, and the two don't contradict each other. That's what I can give."
He put the plastic ruler back in the drawer. The drawer also held the spare car key from the year his son sat his driving test, its plastic casing cracked.
Xiao Gao took the text column.
Along the screen's lower rim ran a scrolling ticker; the characters stood nine pixels tall in the frame, smeared into gray. Xiao Gao aligned and stacked fields A-084 through A-088, ran one pass of super-resolution, and matched the result against forty-six sans-serif faces in the font library. In the end he could read nine characters, two of them not quite certain.
The nine characters read: "pu Nan'an—driving restrictions lifted for three days."
"'pu Nan'an' is missing a character at the front," Xiao Gao said. "I checked the administrative-division tables. Eleven county-level and above place names in the country contain 'pu.' 'Linpu' is one of them—today a county, not a city. The surviving stroke ahead of it starts with a horizontal and tucks in fast on the right. 'Lin' is the highest probability."
"Which means forty years from now, Linpu has been upgraded to a city."
"This one can't be adjudicated," Xiao Gao said. "I listed 41 checkable items: 12 on character-usage standards, 9 on punctuation habits, 6 on measure words, 4 on currency notation, 7 on administrative divisions, 3 on time formats. Forty of them match current standards. The one left over is 'Linpu.'"
He pinned the list to the whiteboard. On its last line, in his own very small hand, he had written: To forge this one item, you would first have to invent a gazetteer—and make it join seamlessly onto the one we have now.
The station-ID column went to Adebayo, because the ID registration number carries a check digit.
The station ID at the desk's edge was the common rounded rectangle, with a string of very fine digits beneath it—six plus one check. The first six digits he declined to call a pattern; he would only say they fell inside the extrapolation band of a serial-growth curve—forty years, not long, not short. The check digit took him two minutes to compute.
"It passes," he said.
"And you're sure the algorithm is the current version?"
"This version was set in 1998 and revised twice; both revisions changed the length, not the polynomial." He spun the pen. "Either it copied the current spec, or it copied the spec from forty years out—and the one from forty years out has the very same polynomial as today's. You pick."
Those two days Tong was busy with something that had nothing to do with the picture.
Last month's ledger had three empty numbers: Machine Six's 0417, 0418, 0419. Everybody knew why—the machine was down three days for the feed-horn retrofit, no data, and whoever was on duty, to save himself the trouble, skipped writing "none" and just jumped the numbers. Institute rule: you write "none" rather than leave a blank. A blank number knocks every later citation out of line.
Now those three blank numbers had become a problem: we had to hang the Layer 1 forensic material into the ledger, and hanging it in meant citing original record numbers—and past the gap, none of the original record numbers lined up anymore.
Tong took a pen and filled in last month's duty log page by page, until one in the morning. He wasn't restoring content. He was restoring "none." Write one "none," sign it, stamp a date. In all he wrote three "none"s.
"Why not renumber the whole thing once and be done with it," Xiao Gao said.
"Renumber," Tong said, "and every document that ever cited the old numbers becomes a forgery."
He closed the record book and put it in the cabinet. The cabinet door never shuts flush; you have to lift it as you close.
That afternoon the hot water went off—boiler room replacing pipe, notice on the canteen door, three days, it said. The aluminum kettle in our duty room boils only half a kettle at a time, and instant noodles had to queue two at a time. Xiao Gao crouched in the washroom rinsing his enamel mug under the cold tap for a long while; the mug had been his grandfather's, he said, chipped in one spot.
That day the signal took its nineteenth step. 03:11:44, neither early nor late. The power went up and nothing else moved—the bandwidth still two hundred hertz, the sync byte still that 0x47, the packet length still 188 bytes. It was like someone who comes to the same window every day to hand in a form, the form filled in fair, never one line more than asked.
What came up on Ye Zhen's side outweighed all three columns.
A catalog table rode at the end of Layer 1. When we first decoded it, in Chapter 3, all we knew was that it was a table: sixteen entries, 64 bytes each, fields cleanly divided—layer number, size, downlink rate, key-hint pointer—and one 4-byte field we took for a checksum, because it was all FF.
Ye Zhen laid the sixteen entries into a matrix by field and read it column by column. She reads things the way a librarian shelves books: her finger walks the row, pauses at some column, her mouth sounding a call number.
"Sixteen entries, and that 4-byte field is FF in every one of them," she said. "All sixteen, FF."
"Reserved field, obviously."
"Reserved fields are usually zeros," she said. "And its position is wrong. Layer number, size, rate, pointer—the ones before it are all ordered by 'how to read this layer.' This field sits between size and rate. It doesn't describe how to read. It describes what this layer is."
She stopped her finger on that column.
"This isn't a missing year. The year field was written over as a reserved value. It's like someone taking a calendar and tearing off the little block where the year prints on every page—months stay, dates stay, weekdays stay, Sundays still in red. You hold it in your hands, everything works, except you don't know which year it is."
Nobody in the meeting room spoke. In the corner the old VCR glowed on, its clock still eleven minutes fast, as it always was; nobody ever adjusted it.
"Torn very neatly," Zhou said. It was the first thing he had said all day.
We merged the three columns' conclusions onto a single sheet. It went up on day nineteen after discovery.
Zhou called a meeting, and the meeting was short. He went through Lao Song's sheaf of printouts, Xiao Gao's 41-item list, Adebayo's check-digit record, and Ye Zhen's field matrix, one at a time; midway he twisted the thermos, couldn't open it, pushed it aside, and kept reading.
"The eclipse item," he said. "March 2, 2116, off by 1.7 degrees. Lao Song, can you kill that 1.7?"
"I can't kill it," Lao Song said. "I can say it looks more like 2079."
"More like is not evidence."
"No."
"Then write: two candidates, the former favored," Zhou said. "When more frames come in, we come back and weigh it again."
He squared the four documents into a stack, slid them into a yellow archive envelope, and wound the string three times around the flap. Then he had Tong bring the 4-terabyte drive—raw baseband, the 105 decoded frames, every intermediate product, all of it on there.
Tong stood at the table's edge holding the drive, waiting.
Zhou opened the safe in the corner—an institute antique from the nineties, a scratch through the paint on the door, the dial clacking as it turned. He set the drive inside, pressed the yellow envelope on top of it, shut the door, and spun the dial two turns.
"From today, this drive lives here," he said. "To use it: register, and two people open it together."
"Dr. Zhou," Adebayo said, "then what do we analyze?"
"Copies. The copies don't leave the institute."
"How is that any different from locking it?"
"The difference," Zhou said, "is that until forgery is proven, it doesn't exist."
He took his hand off the dial and looked at us.
"I mean outwardly," he said. "For ourselves, it exists once every morning at three eleven and forty-four seconds. The two things don't conflict."
Tong raised his hand, raised it halfway, and put it down.
"Dr. Zhou. Do we report this upstairs?"
"Yes."
"To what level?"
"Per the schedule," Zhou said. "This month's schedule item to report reads: suspected artificial narrowband signal, bearing Cassiopeia, local interference being excluded. As of today, every word of that sentence is true."
"And the eclipse item?"
"The eclipse item is not on this month's schedule."
Tong asked nothing further. He wrote a line in his notebook; the pen point punched through the paper as he wrote.
The meeting broke up close to ten. Half the corridor lights were broken; the other half were sound-activated, and you had to stomp.
That night I had the back half of the shift.
In the duty room a single workstation was running integrations, the fan sound steady. My father's Red Lantern sat at the corner of the desk; I switched it on and turned the band knob to 7.2 megahertz—no station, only static. His rule, in life, was ten minutes of static first, then hunt for stations; it kept the ears true, he said. I used to think that was just a lazy way of not tuning.
Outside, someone in the parking lot was trying to start a car; the third try caught.
At twelve thirty I called home. Six rings; then it was Nian, with the voice of someone woken out of sleep, coming awake one layer at a time.
"Mama."
"Why aren't you asleep."
"I slept," she said. "Teacher says the staccato in my third variation is too heavy. It should sound like someone going up on tiptoes."
"Then try going up on tiptoes."
"I'm in bed."
"Then tomorrow."
"Are you coming home tomorrow?"
I said something; what exactly, I couldn't tell you afterward. She hung up first, and just before, there came a loud plastic knock in the receiver—she had dropped the phone on the floor.
The screen still showed the two missed calls I had dismissed that afternoon, both from the piano teacher. Beneath them, the text: Hello, Lin Nian's mama—there is a recital class Saturday morning, April 11; parents are welcome to come and listen. Your daughter hopes you can be there.
I turned the phone face down on the table.
Inside the static one patch ran especially thick, like someone very far away turning a plastic sheet. One winter my father had caught a woman's voice on this frequency, reading numbers; it broke off at seven. He had logged one line in the band log: unknown station, female voice, reading numbers, stops at seven. Pencil; the point too sharp; it had nicked the paper.
I didn't follow it further.
At three oh four, the workstation popped a window. The little stretch the Layer 1 key-hint pointer indicated had decoded.
It was a job Tong had set up two days earlier: in the catalog table, Layer 2's entry, its key-hint pointer aimed at a 512-byte block at the layer's end. Until now we'd had the structure but not the content. This time the automated run went through.
I opened it.
Of the 512 bytes, the first 12 were a string of ASCII, plaintext, no checksum:
`1987/TV/CN`
Behind it, 496 bytes of binary. One frequency-domain transform and I saw what it was: an audio fingerprint. Sixteen time slices, thirty-one mel-band energy ratios per slice, quantized to 8 bits. 1.2 seconds.
I had no source audio; a fingerprint doesn't run backward into sound. All I knew was this: inside those 1.2 seconds somebody said one sentence. The speaker was Chinese. The year was 1987. The occasion was a TV drama.
Now I knew what Layer 2's lock wanted. Not a password. That line—a line somebody said in some TV serial in 1987, typed in one character at a time.
I saved the result, catalog number B-001. Then I wrote one line in the duty log's remarks column:
Layer 2 key hint decoded. Plaintext 1987/TV/CN, with one 1.2-second audio fingerprint attached; content is one line of dialogue from a 1987 domestic TV serial, pending retrieval.
When I finished I checked my watch: three eleven. On the forty-fourth second, step twenty-three came up.