74: Chapter 74 Embers in Metal

Spring of the twenty-third year came a bit earlier than previous years.

The electronic calendar showed that the time was approaching the vernal equinox.

As for whether the drift came from precession, changes in the axis of rotation, or the cumulative error of the Wasteland time baseline itself, he did not have enough data to judge right now.

In short, the vernal equinox drifted by a few hours to a few days every year.

That perpetual calendar algorithm based on the Old Era in electronic devices had long become a placebo with black humor.

He trusted the strip of Moss beneath the Stone House base more.

Starting from the end of winter, they would struggle out a little bit of green from the dormant grayish-brown.

When this greenness, like a slow paint, overflowed the third stone on the base, it meant that the lowest nighttime temperature had stabilized above zero.

The window for the expedition officially opened.

On the last day of the twenty-second year, when he finished writing that ten-year summary of documentary history in front of the north wall, the green of the Moss strip had only overflowed the lower edge of the third stone.

In March of the twenty-third year, this touch of green finally arrogantly crossed the boundary, even spreading towards the crevices of the fourth stone.

"It's time to set off."

Jiang Lin began to pack.

The first category: those that can measure magnetism.

This was the core of his trip: a three-axis magnetometer with a nominal resolution of 0.1 nT.

Although the manual bragged to the heavens, Jiang Lin knew very well in his heart that the effective field accuracy entirely depended on temperature drift, probe attitude, and calibration status.

This kind of equipment was most afraid of temperature drift and attitude errors, starting to babble at the slightest temperature fluctuation.

Next was a set of self-made Helmholtz coils he was proud of, used to check the probe zero point, three-axis ratio, and that day's temperature drift.

Finally, a set of portable fluxgate probes served as a backup for cross-validation.

Doing observations meant one could never trust just one set of data.

The second category: those that could still retain on-site information after the samples returned to the Stone House.

Forty-eight sample bags, each independently numbered, a mechanical scribing tool, a paper orientation recording board, a north-seeking prism, and three field notebooks.

The third category: those that could keep him alive to return.

Exoskeleton, seven-day emergency food, twelve liters of drinking water, windproof tent, sleeping bag, first aid kit, spare batteries.

The total weight of the inventory was twenty-nine point four kilograms, within a controllable range.

At six in the morning, Jiang Lin switched the controller of wind turbine no. 2 to automatic mode, replaced Observation Point A and B with high-capacity backup cards, and performed a full discharge and charge cycle on the batteries in both places.

At seven sharp, he shouldered the carrying frame and set off.

The edge of the Moss strip was still covered with a layer of thin frost, making a faint cracking sound when stepped on.

The metal support bars of the exoskeleton were somewhat stiff in the low temperature, and every step he took made the sound of the pawls dropping into teeth crisper than it sounded in summer.

The substation was in the north-northeast direction.

That was a landmark he caught a distant glimpse of with a telescope when he climbed an abandoned signal tower to escape a sudden electromagnetic storm during the fifth expedition.

The straight-line distance shown by the rangefinder at that time was about thirty-eight kilometers.

Unfortunately, there were never straight lines on the Wasteland.

The landforms here had been reshaped by some unknown disaster.

To cross these thirty-eight kilometers, he had to traverse gravel slopes full of hidden pits, bypass quicksand belts that could swallow a person without leaving even a trace of slag, shuttle through wind-eroded gullies like a rat, and constantly watch out for cliffs and sharp metal wreckage half-buried in the soil.

Thirty-eight kilometers would ultimately be ruthlessly stretched into more than fifty kilometers.

This was a three-day journey.

On the first day, he walked faster than expected.

By three in the afternoon, he had advanced fourteen kilometers.

But while crossing a gentle slope, the ratchet on the left leg of the exoskeleton suddenly made a strange click, followed by a slight rebound delay.

He immediately stopped, let his center of gravity sink accordingly, knelt on one knee, and pulled a multi-functional wrench out of the tool kit at his waist.

He had seen this malfunction twice before.

The wind and sand were too heavy, and tiny quartz sand particles had drilled into the dust cover of the actuator.

He patiently removed the outer shell, blew away the grit with a gas cylinder, and squeezed a little precious synthetic grease into it.

After reassembling, he moved his left leg; it was fine.

He then recorded this malfunction with an abbreviation and continued moving forward.

On the second day, trouble arrived.

On the originally flat Gobi desert, a strangely colored dark yellow area appeared.

That was a quicksand belt, looking like solid sandy ground on the surface, but underneath was a mud trap formed by groundwater level fluctuations.

Jiang Lin had to make a detour of four kilometers, carefully cutting across along the edge of the quicksand belt.

On the morning of the third day, the terrain began to undergo significant changes.

The flat tableland began to sink in a large area, as if a giant had stepped heavily on the earth.

At the southwest corner of the tableland, several collapsed transmission towers lay haphazardly on the ground like dead steel behemoths.

That was a landmark seen during the fifth expedition.

Seeing the transmission towers meant he was almost there.

Climbing up the final low slope.

When he stood firm and wiped the dust off his goggles, the substation finally appeared in his field of vision without reservation.

In his memory, it was only a blurry ruin through the telescope.

But now, standing on the edge of the tableland and overlooking from above, he truly saw the full picture of this behemoth for the first time.

The occupied area was astonishingly large, visually estimated to be at least twelve thousand square meters.

The overall shape was a rigorous rectangular layout, with the long sides extending along the east-west direction, meticulously planned as if unified according to some engineering standard.

On the west side was a two-story concrete main workshop.

Most of the walls had collapsed, like a paper box smashed by a punch, leaving only two gable walls on the east side standing abruptly, exposing the severely rusted equipment skeleton inside.

To the east of the workshop was the core transformer area.

Four sets of bulky transformers sat on half-a-man-high concrete bases.

Their outer shells had been polished away by years of wind and sand, and the busbars that originally wrapped the insulation layers had long fallen off.

To the north was the switchyard.

The steel structure supports still stood stubbornly, but the ceramic insulators on them were all shattered, scattering into a pile of white debris on the ground.

The huge metal blade switches were tightly bitten by the oxide layer, completely rusted to death in the open state.

At the east end was a small brick-concrete building about six meters square.

The door had long since disappeared without a trace, and the glass on the windows was shattered without even a shred left.

The outermost periphery of the substation was a circle of collapsed courtyard walls.

The concrete of the walls peeled off in large areas, but the thick reinforcing steel mesh inside could still faintly reveal its original continuous direction in some places.

Jiang Lin unloaded the heavy carrying frame, taking only the lightweight three-axis magnetometer, and began a long and tedious circular scan along the outside of the wall.

The peripheral magnetic field was very stable most of the time.

However, when he walked near several areas where the steel mesh of the wall remained continuous, the readings on the magnetometer's screen began to show regular deviations.

The magnitude of the deviation was not large, only a few nT, but Jiang Lin's eyes lit up instantly.

This was a magnetic field shift with a clear directionality.

He took out his field notebook and quickly recorded the orientation, distance, and specific deviation values of these abnormal points in the wind.

At three in the afternoon, the sun began to tilt westward.

Jiang Lin pitched camp in a leeward low-lying area one hundred and twenty meters away from the wall.

This distance was precisely calculated by him, enough to avoid the direct pollution of the camp's background baseline measurements by the large metal components inside the station.

At the same time, it could maintain line of sight to the substation entrance and the edge of the tableland, making it convenient to evacuate in time if weather or surface anomalies occurred.

After the tent was pitched, he drank a couple of sips of water, put on his dust mask, and truly stepped into the interior of the substation for the first time.

The wind passed through those collapsed steel frames and uneven walls, making a thin and sharp whistling sound.

Metal fragments, large chunks of concrete, and twisted wires were scattered randomly on the ground.

Occasionally, a few pieces of green glass reflected dazzling sunlight in the sand, their edges rounded by the wind and sand.

Jiang Lin picked up a piece to look at it, and it looked like the wreckage of a glass cover on some old-fashioned industrial instrument panel.

He walked unsteadily along the rubble-filled passage between the main workshop and the transformer area.

When he walked to the center of the transformer area, Jiang Lin suddenly stopped, kicked away a layer of floating sand on the surface with the toe of his boot, revealing the remaining metal grid below the floor.

It looked like the standard grounding grid of a substation.

The concrete covering it had been peeled off by severe weathering, and most of the metal grids were exposed, covered in rust.

Only in a few areas near the transformer bases was this layer of grid still stubbornly embedded in the incomplete concrete.

Jiang Lin squatted down and measured it with a vernier caliper.

The mesh was close to square, with a side length of about three centimeters.

The rust layer on the cross-section of the wire was distinct, with the outer layer being dark red iron oxide and the inner layer being dark brown.

This should have been a low-carbon steel galvanized wire, but that anti-corrosion galvanized layer had long been worn away in the years unknown how long ago.

He squatted down beside the first fragment embedded with the metal grid, took out the special steel mechanical scribing tool, and forcefully carved a set of numbers on it.

[V-OBS-01]

Immediately afterwards, he carved the second number on another fragment a few meters away.

[V-OBS-02]

Throughout the afternoon, like an untiring ant, Jiang Lin numbered a full nineteen observation points around the four sets of transformers and the main workshop.

Every observation point strictly corresponded to a metal component or metal grid that might still retain remanent magnetization information.

As the sky gradually darkened, he turned on his flashlight and walked into the control room.

The interior had been hollowed out.

Instrument panels, consoles, relay matrices, wiring troughs...

All had vanished into thin air.

Only the door frame remained on the wall.

Jiang Lin squatted down, clamped the remaining metal liner with a mechanical micrometer, tightened the knob, and glanced at the scale.

Forty-two millimeters.

He was stunned for a moment, sweeping the beam of his flashlight carefully across the cross-section of the door frame.

The cross-section was not a single-layer steel plate; a multi-layer composite structure could be seen, with a darker-colored and softer-textured metal layer sandwiched in the middle.

As for whether it was a lead layer, a copper layer, or some kind of shielding material, he lacked the on-site conditions to confirm.

But this kind of door frame was clearly not prepared for an ordinary control room.

This was getting a bit interesting.

An ordinary civilian substation control room didn't need a composite door frame of this thickness and material at all.

Even less did it need those high-strength load-bearing hinges fixed on the door frame that were exaggerated as if used to lock a vault door.

This showed that a heavy protective door with extremely strong electromagnetic shielding and even explosion-proof functions had once hung here.

Jiang Lin recorded this detail in his notebook, exited the control room, and turned to walk into the main workshop.

The scene inside the workshop was even more chaotic.

The foundation of the giant rotating equipment still stubbornly remained, astonishingly large in volume, exceeding two stories in height.

But the generator body had long disintegrated, leaving only a thick rotating shaft that required two people to embrace, yet was severely bent, and a few rotor winding fragments scattered in the corners.

Those wires that should have originally been copper-colored had long oxidized into a deep green.

Jiang Lin walked up to a surviving load-bearing wall and knocked on the wall body with the metal handle of the multi-functional wrench.

The sound was very deep, muffled enough to make one's heart flutter.

He measured on a cross-section produced by cracking.

The thickness of the load-bearing wall was about sixty centimeters.

And at a collapsed section of the outer wall, the intricate steel reinforcement skeleton inside was exposed.

Jiang Lin roughly estimated that the diameter of the steel bars reached an astonishing twenty-eight millimeters, and the arrangement density far exceeded the construction standards of ordinary substations.

He quickly calculated in his mind.

An ordinary substation didn't need such thick explosion-proof walls, didn't need such thick steel mesh, and even less did it need that forty-two-millimeter-thick composite anti-radiation shielding door in the control room.

This was not an ordinary substation.

It might belong to some higher-specification, deeper-level engineering system.

Its carrying target was unknown, but it was definitely designed to resist nuclear strikes, strong electromagnetic pulse events, or other extreme disaster environments.

Subsequently, while clearing a pile of rubble next to the transformer number 1 base, he discovered a metal nameplate pinned underneath.

Due to long-term exposure and erosion by wind and sand, the surface of the nameplate had been polished almost white, and only a few incomplete sets of handwriting could be barely discerned.

Jiang Lin wiped away the floating dust on top, turned on the high-intensity flashlight, and leaned in to examine it closely.

TM-

Grid

Power Distribution

Great Wall

A total of four groups of residual characters.

First group: TM-, which was obviously a prefix of some kind of numbering.

He had never seen the abbreviation TM- in the existing databases, at least not in the public power grid numbering systems he was familiar with.

Second group: Grid.

This should be the last character of some kind of network, but unfortunately the preceding parts had been worn away.

Third group: Power Distribution.

This group was relatively ordinary, but placed together with the network numbering of TM-, it made Jiang Lin feel that this so-called power distribution was by no means as simple as supplying power to tens of thousands of surrounding residents; it might be a sub-node of a transcontinental super network.

Fourth group: Great Wall.

Seeing these two characters, Jiang Lin's breathing paused slightly for half a second.

Great Wall.

In the civilian industrial system of the old era, almost no one would use this word as a prefix for facilities.

This word still carried quite a bit of weight.

Pieced together like this, the four groups of residual characters formed a vague yet massive shadow in Jiang Lin's mind.

[TM-?? Grid / Power Distribution / Great Wall...]

He repeatedly examined it several times, and even tried to shine the flashlight from different angles, attempting to restore more letters through the tiny depressions on the metal surface, but unfortunately, the rest of the nameplate had been completely leveled by time.

He did not continue to guess blindly downward.

In Physics, the most taboo thing was to let one's mind wander when evidence was insufficient.

He simply transcribed the residual characters of the nameplate stroke by stroke into his notebook, then raised the camera and conducted an omnidirectional micro-photography archiving of the nameplate from multiple angles.

The next morning, Jiang Lin began his formal measurement work.

He first set up the Helmholtz coil in the open space of the camp.

This set of devices could not eliminate the Earth's own background geomagnetic field.

Its function was to generate a calibration magnetic field of known magnitude and direction after being powered on.

Jiang Lin put the magnetometer probe into it to check whether the probe's zero point had drifted, whether the three-axis scale factors were correct, whether there was any problem with inter-axis coupling, and whether that day's temperature drift had grown large enough to turn the data into garbage.

Half an hour later, the calibration was completed, and all indicators were within the tolerance range.

Jiang Lin shouldered a messenger bag filled with sample bags and tools, and with the magnetometer, entered the substation once again.

The first observation point, V-OBS-01.

Jiang Lin knelt on the ground, first using a mechanical scribing tool to laboriously carve a cross mark on the surface of the concrete fragment.

The long axis of the cross was strictly aligned with magnetic north, and the short axis with magnetic east.

This was to ensure that after knocking off the sample and bringing it back to the Stone House dozens of kilometers away, he could still restore the sample's in-situ posture in the laboratory; this step absolutely could not be omitted.

Without remanent magnetization measurement in three-dimensional space posture, even if measured to perfection, it would still be a pile of waste paper.

After completing the posture calibration, he brought the magnetometer probe close to the surface and read the in-situ data.

Bx = -47.3 nT.

By = +12.6 nT.

Bz = +3.2 nT.

When he was about to pry off this sample, he found that the concrete weathered for decades was more brittle than imagined.

As soon as the hammer tapped on it, with a snap, the entire surrounding circle cracked.

Jiang Lin frowned slightly, immediately changing his strategy to peel off and take a small core about the size of an egg using an engineering shovel.

He placed it into a sample bag, sealed it, and affixed a barcode label.

Immediately following was the second observation point.

Bx = +51.7 nT.

Jiang Lin's hand holding the instrument paused for a moment.

The sign was reversed.

But the absolute value was shockingly close.

He raised his head, his gaze moving back and forth between the two points V-OBS-01 and V-OBS-02.

One was in the southeast, and the other in the northwest.

If a virtual connecting line was drawn on the diagonal of this transformer base, the direction of the magnetic field deviation presented a nearly perfect anti-symmetric state.

He suppressed the throbbing in his heart, did not jump to hasty conclusions, and continued on to the third observation point, and then the fourth.

When the data for the fourth point came out, Jiang Lin sat down heavily on the dust-covered ground.

He tore off a sheet of grid paper, drew the positions of these four points with a pencil, and then drew vector arrows representing the horizontal magnetic field direction based on the measured Bx and By components.

On the paper, the four points connected into an irregular quadrilateral surrounding the transformer base.

And those four vector arrows, as if chasing each other's tails, presented a clear annular trend.

At this very moment, Jiang Lin truly stopped the work in his hands.

Faced with such overly perfect data regularity, a qualified Physics scholar's first reaction was definitely not wild joy, but vigilance.

The first thought that popped into his head was: "Find counterexamples."

Did the instrument drift?

Without saying a word, he immediately packed up his things, ran back to the camp, and shoved the probe back into the Helmholtz coil for secondary calibration.

The results showed that the zero point remained stable, and the probe had no obvious drift.

Was the local natural geomagnetic field inherently uneven?

He took the instrument, walked to an open space thirty meters away from the wall, and conducted a ten-meter-by-ten-meter baseline scan in a place without the interference of metal ruins.

The readings were as steady as stagnant water, and the background magnetic field was very uniform.

Was it local interference caused by those scattered steel rebar skeletons?

This possibility could not be completely ruled out.

The large transformer base itself had a huge mass, coupled with the remaining silicon steel core, high-density rebar, and the underground grounding grid, all of which could cause extremely complex magnetic anomalies.

Yet Jiang Lin couldn't help but think: if it were merely scattered rebar interference, the magnetic field it generated should be chaotic and disorganized.

It shouldn't present such a highly consistent, co-directional geometric sense of organization across multiple closed loops spanning dozens of meters.

Observer bias?

It existed.

People always tended to look for the patterns they wanted amidst chaos.

But he quickly corrected himself: these nineteen observation points were numbered in advance, prior to conducting magnetic field measurements, based solely on the visible state of the remaining metal.

He hadn't gone around scanning with the instrument first, intentionally picking places as sampling points wherever the data looked like a ring.

Although the risk was reduced, it was not zero.

Jiang Lin opened his field notebook and heavily wrote on the last line of that day's log:

[Observer bias risk assessment: Low - Moderate.]

[Annular trend: Preliminarily confirmed to exist. Continue to expand sampling.]

Over the next four days, Jiang Lin seemed to have turned into an untiring mining machine.

The world was left with only four actions: sampling, calibrating posture, in-situ reading, and sealing and packaging.

From nineteen observation points, he ultimately collected forty-seven valid samples.

In the following two days, to ensure the rigor of the data, he successively collected eight additional control samples in different areas on the periphery of the substation.

These samples were also concrete fragments and metal scraps, but their positions were not on any current loop of the original power grid.

The numbering ranged all the way from [V-CTRL-01] to [V-CTRL-08].

As expected, the in-situ magnetic field deviation readings of all control samples were close to the local baseline, showing no organized directional deviation.

On the seventh day, Jiang Lin, whose physical stamina consumption had reached a critical value, persevered and conducted a complete loop scan along the outer wall.

The result was shocking. On the steel rebar mesh segments on the west and north sides that still maintained continuity, there also appeared weaker but similarly directionally organized magnetic deviations.

They were between approximately 5 and 12 nT.

Meanwhile, around the generator base of the main factory building, the annular deviation was even more intense, reaching 30 to 40 nT.

In contrast, inside the control room, there was none.

On the fractured wall sections, there was none.

In the open space, there was none either.

At this step, a grand image hidden at the level of Physics was already uncontrollably emerging from the ruins.

Large rotating equipment, transformer bases, continuous grounding grid segments.

The directions of remanent magnetization left behind by the metal components in these places that originally constituted closed current loops in engineering all exhibited a regular annular distribution.

As for the isolated metals that did not form current loops, they did not have any annular magnetization.

On the morning of the tenth day, Jiang Lin embarked on the return journey with fifty-five samples.

On the evening of the thirteenth day, the setting sun was like blood.

Jiang Lin returned to the Stone House stronghold.

On the roof, the blades of wind turbine no. 2 were still rotating steadily and tirelessly.

In the distance, the green indicator lights of Observation Point A and Observation Point B flickered like fireflies in the twilight.

Everything was as usual.

These four words on the Wasteland were the most beautiful poem.

Jiang Lin took out the fifty-five sample bags one by one, arranging them neatly on the stone table in numerical order.

He then went to wash his face, boiled some water, and brewed a cup of slightly bitter Moss tea.

Fifty-five samples.

Each one was very small and dusty, looking just like garbage casually picked up in the ruins of a construction site.

Yet they might be the first substantive physical evidence handed over to him by this boundless Wasteland actively speaking since the Great Collapse.

Jiang Lin drank the tea in one gulp, opened the workstation, and created a new folder.

[RECON-VC-01]

Substation Remanent Magnetism Reconstruction - Project Zero One.

The location of this folder was completely different from the previous six folders in his computer dedicated to stacking theoretical deductions.

The first six belonged to paper, belonging to mathematical deduction.

While this one belonged to the site, belonging to reality.

Over the next full year and a half, Jiang Lin reserved the few hours each day when his mind was most active and his energy most vigorous entirely for these fifty-five samples.

He cleared out a two-square-meter workspace in the corner on the west side of the Stone House.

On the table were placed his prized set of Helmholtz coils and triaxial magnetometer.

Next to it was a sample holder, used to ensure that the sample's posture in the calibration magnetic field was absolutely fixed.

In addition, there was a set of constant-temperature water bath devices to control the temperature of the sample during the measurement process, avoiding magnetic drift caused by environmental temperature changes.

As well as a set of extremely power-consuming alternating demagnetization coils.

Demagnetization—this was the most crucial and tormenting step in the entire analysis.

Its principle was to peel off the remanent magnetization components of the sample step by step by applying a continuously weakening alternating magnetic field.

To put it colloquially, this was like doing a stratigraphic CT scan on a metal fossil.

Jiang Lin didn't want to know what the current magnetism of this stone was like; he wanted to wash away layer by layer the low-coercivity noise points left on the surface by lightning and friction over decades, to see the magnetic field inside the core.

The first sample to go on the workbench was still V-OBS-01-A.

Jiang Lin fixed it strictly according to the sampling posture recorded in the field, with its long axis locked firmly onto magnetic north.

First, he did coil calibration; everything was normal.

Then he turned off the external magnetic field, held his breath, and measured its own natural remanent magnetization.

Bx = -42.1 nT.

By = +11.3 nT.

Bz = +2.8 nT.

Jiang Lin let out a long sigh of relief.

The direction was very close to the in-situ readings, which indicated that the bumpy transportation disturbances over the past dozen days had not erased the information inside the sample.

Subsequently, the long alternating demagnetization began.

He cautiously adjusted the knob, starting from 5 mT, increasing it step by step to 100 mT, and for a few key samples, he boldly pushed it to 200 mT.

After each level of demagnetization ended, he had to take out the sample, measure the remanent magnetization again, and record the changes in the data.

The temporary magnetization components with low coercivity were stripped away layer by layer.

What remained were the high-coercivity remanent magnetization components that were more stable and less easily rewritten by later disturbances.

Processing the first sample took a full three hours and forty minutes.

Although the chart data drawn in the end wasn't very pretty and had many burrs, this was enough for Jiang Lin to confirm a crucial fact.

The remanent magnetization of V-OBS-01-A probably didn't come entirely from the instantaneous magnetization generated when a large piece of soft magnetic steel was struck by lightning.

Its characteristic curves indicated that this magnetism was more likely carried by stable fine-grained magnetic mineral phases generated after the rebar rusted.

This ruled out the temporary magnetization caused by friction and collision during transportation.

As for whether it came from the strong transient field during the catastrophe, it still required subsequent thermal demagnetization and control sample support.

But it at least possessed the physical characteristics of long-term remanent magnetization.

As for whether this memory can be traced back to the exact moment the disaster occurred, it still depends on subsequent thermal demagnetization experiments and the data from those control samples.

The next day, the second sample.

The third day, the third sample.

...

Scientific research is never about daily epiphanies, nor is it the romance of saving the world by typing a few lines of code as seen in movies.

It is dealing with a pile of earth-scented stones every day, and facing a series of headache-inducing garbled codes.

Jiang Lin could only process one to two samples a day.

Testing samples by day, tending to the life-sustaining farmland and checking the outside observation points in the evening, and staying up with bloodshot eyes at night to back up data.

When some samples were heated for thermal demagnetization, internal chemical reactions occurred, phase transitions completely destroyed the magnetic domains, and the data was instantly invalidated.

However, the demagnetization curves of some samples were surprisingly clean, with directivity as clear as textbook illustrations.

Still others lost all their remanent magnetism in the low-temperature range and could only be regretfully classified as late-stage geological environmental disturbances, being weeded out from the core dataset.

Good-looking data, ugly data—Jiang Lin treated them all equally and entered them all into the database.

Winters went and springs came, the numbers on the calendar flipped over and over.

Five hundred and forty-seven days later, the analysis of these fifty-five samples was finally completed.

It was time to start integrating the data.

He wrote a Python script himself.

This script, like a tireless weaver, read every sample number, spatial coordinate, sampling 3D attitude, in-situ reading, alternating demagnetization spectrum, and thermal demagnetization result, automatically subtracting the background baseline of the control samples.

Pressing the enter key.

The screen flickered once, and then a visual chart of the two-dimensional remanent magnetic vector field began to slowly generate on the black background.

Red arrows slowly emerged one by one.

Each arrow represented a sampling point.

The direction of the arrow pointed to the horizontal remanent magnetization component, and its length represented the magnetic field strength.

The first group of annular structures came out.

Its center fell precisely on the base of the missing generator in the main factory building.

Soon after, the second group of rings came out.

The position perfectly corresponded to the foundation of transformer no. 1.

Then came the second, third, and fourth foundations.

The continuous steel mesh on the outer wall also outlined a closed loop that was weak but had an extremely large span.

And at the coordinates of the control room, there was nothing.

On the open ground, there was nothing.

Where the wall broke, it was also a blank slate.

Jiang Lin felt his heart pounding wildly in his chest.

What this chart presented was by no means the simple, straight long current sheet described in the papers by Sweet and Parker.

Nor was it the elegant X-type magnetic reconnection geometry proposed by Petschek.

Nor was it the strings of isolated magnetic islands in the recently popular Plasmoid model.

It was a bunch of mutually nested closed loops.

These were broken industrial conductive networks one after another.

At the exact moment when that unknown disaster struck back then, they were like massive passive coils, using the remanent magnetism remaining inside the metal to permanently brand the direction of the terrifying induced current they had endured at that time into their own bodies.

This was like a current map sintered onto the ruins by the fire of the disaster, never fading.

Jiang Lin leaned back in his chair, raised his head, and let out a long breath.

The magnetic field structure left behind at the real disaster site was far more complex than the models imagined out of thin air by the human brain.

At least at the regional level of the substation, what it presented was a multi-loop, multi-scale, mutually nested, and even mutually interfering magnetization geometry.

He closed his eyes and, following this logic, frantically carried out scale extrapolation in his mind.

What if it wasn't just a substation?

What if the response of this closed structure was magnified to the scale of the entire planet?

The planet's ionosphere is a conductive spherical shell, the magnetosphere is flowing plasma, there are metal-rich conductive rock layers underground, the oceans are natural giant conductive liquids, coupled with the global ultra-high-voltage power grids built by humans, and large space metal facilities that might be floating in near-Earth orbit...

What if all these huge closed conductive structures produced a collective response during a certain extreme cosmic-level electromagnetic event?

The image of the real current tearing between heaven and earth, the ultimate force causing the Great Collapse, could never be as clean and refreshing as the lonely, monotonous current sheet drawn in textbooks.

It must be a violent, multi-dimensional, entangled electromagnetic storm.

During the period between the twenty-fifth and twenty-sixth years, Jiang Lin fell into deep contemplation.

Facing this data, he repeatedly reviewed four possible Physics explanations.

The first kind: extreme induced current.

A strong electromagnetic disturbance from outer space, such as extreme solar activity, abnormal charged dust streams / plasma structures, or other unidentified cosmic environmental events.

According to Faraday's law of electromagnetic induction, a huge transient current is excited in all closed conductor loops.

The powerful magnetic field generated by this current instantly magnetized all ferromagnetic substances along the way.

Jiang Lin evaluated it as logically compatible.

The second kind: steady-state magnetic field during the operation of old equipment.

Generators and transformers operated under high load for a long time back then, and their stray magnetic fields would also slowly magnetize nearby matter.

The evaluation was partially compatible.

However, the steady-state field strength of daily operation was too weak to easily explain the overall strength measured now, let alone why the steel mesh of the long-span wall and the core equipment presented simultaneously organized directions.

The third kind: re-magnetization after fire demagnetization.

A high-temperature fire was triggered during the cataclysm, exceeding the Curie temperature, causing the original remanent magnetism of the building materials to be randomized.

When the fire went out and the temperature dropped, they were re-magnetized in the local geomagnetic field.

His evaluation was partially incompatible.

If it cooled in the local geomagnetic field, then all remanent magnetization directions should uniformly point to the local geomagnetic field direction, rather than presenting a circular distribution along the original current loops like it did now.

The fourth kind: the electromagnetic pulse event of the disaster itself.

This was a special and more terrifying version of the first explanation.

If the source that triggered the disaster and exterminated humanity was itself an extreme electromagnetic pulse attack or mutation capable of destroying half the earth, then this substation prefixed with the Great Wall not only failed to defend against it, but instead became a passive, massive recorder.

Jiang Lin's evaluation was that it was logically completely compatible, but lacked broader external evidence.

He sat in front of that blank sheet of paper filled with formulas and derivations, looking at it for a long time.

In the end, he didn't stamp any of these four explanations with an absolutely correct seal.

He opened the keyboard and typed a rational verdict in the metadata text of [ RECON - VC-01 ].

[Comprehensive Evidence Level: E]

[Compatible Explanations: Extreme Induced Current / Disaster Electromagnetic Pulse / Old Equipment Steady-State Magnetic Field / Re-magnetization After Local Fire.]

[Strongest Compatible Direction: Extreme Induced Current / Disaster Electromagnetic Pulse.]

[Independent Veto Items: None.]

In the scientific evaluation system, the meaning of Level E evidence was very clear.

It provided a very clear physical picture.

However, it was still compatible with at least two mutually independent explanations.

It could neither conclusively verify any existing magnetic reconnection model nor strongly veto any theory.

It still could not explain the mysterious red belt that existed year-round above the Wasteland.

But it was not without value.

Because it was like a bolt of lightning, splitting open the fog in Jiang Lin's mind and illuminating a brand-new direction.

Multi-loop, multi-scale, mutually entangled real current systems.

This was an untrodden wilderness.

Jiang Lin stood up and walked over to the huge wall on the north side of the Stone House.

That was a manually drawn map of the research history of magnetic reconnection by him.

Sweet, Petschek, Plasmoid, Hall effect, turbulence model, tearing mode instability...

The names and theories of countless scientific giants of the old era all had their own territory on the wall.

But in the upper right corner of the wall, there was a large blank space.

Not a single area started from the perspective of how the macroscopic conductive network of a complete planet collectively responds to a disaster.

That was a scientific no-man's-land.

Jiang Lin looked at that blank space, his fingers unconsciously rubbing the shaft of the pencil.

He did not immediately fill it with formulas.

To grow a brand-new, self-consistent physical picture from this pile of rusted stones would not take a few years.

This might take decades, or even hundreds of years.

After long contemplation, he sighed and just wrote a serial number in tiny font at the edge of that blank area.

[ RECON - VC-01 ]

In the early autumn of the twenty-sixth year, all fifty-five samples were properly archived.

They were sorted and packed in sealed boxes, stored in numerical order on the sample rack in the southeast corner of the Stone House.

On the side of each box was a detailed label attached, accompanied by in-situ records, alternating demagnetization curves, thermal demagnetization results, and the version number of the Python script used when analyzing these data.

Jiang Lin stood in front of the rack, patting the dust off his hands.

"Wait for the next expedition," he said to the air.

Next time, he might be able to buy a vibrating sample magnetometer, assemble a more stable alternating demagnetization device, or a high-temperature furnace with more precise temperature control.

By then, this Level E evidence might be upgraded to Level D, or even a decisively significant Level C.

Of course, it might also be ruthlessly beaten back to its original form in front of new data, proving that his painstaking efforts over the past few years were all unrequited passion.

But the samples were placed there like silent truths.

They would never easily change the historical direction they recorded simply because of the observer's expectations and obsession.

In the evening of September 17th of the twenty-sixth year.

The evening breeze brought the chill of early autumn.

wind turbine no. 2 rotated steadily, and in the distance, the indicator lights of Observation Point A and B flickered slightly in the gradually thickening twilight, as if exchanging secret codes among companions.

Jiang Lin raised his head.

At the end of the northern low sky, that familiar light red bright band appeared once again.

He stood quietly at the doorway like this, looking at it.

Without trying to forcibly explain its spectrum, nor jumping to any arbitrary conclusions.

Just at this moment, he suddenly felt that the red line didn't look like some isolated atmospheric optical phenomenon in the sky at all.

It was more like an endless, huge system, revealing a tiny trace inadvertently from a very distant place.

And the fifty-five samples from the substation that he finally archived in the computer today were merely touching the tiniest, roughest metallic embers at the very edge of this behemoth while blind men touched an elephant.

The vastness of the universe and the profoundness of the disaster were vividly displayed before this red line.

Jiang Lin watched for a while, withdrew his gaze, sat back in front of the workstation, brought up the summary document of the [ RECON - VC-01 ] project, moved the cursor to the last line, and with the crisp clicking sound of the keyboard, wrote down his next command to himself.

[Next step plan: Expand the scanning radius and rearrange a more macroscopic observation baseline network.]