The Equation on the Tombstone

Nevada Desert, March 17, 2085, Dusk

Erin's boots crushed the siliconized sand beneath her, making a sound like glass shattering. The radiation counter had long fallen silent, replaced by the tingling under her skin—her bone marrow was being quantumized, and she could taste the metallic sweetness of iron decaying into plutonium in her blood.

A stone tablet appeared in the center of the nuclear blast crater, its surface showing no signs of weathering. It was made from a self-observing material: when looked at directly, it was basalt, but from the corner of the eye, it flowed like a Klein bottle structure. The first inscription made Erin fall to her knees:

∇×E = -∂B/∂t + λ(ψ†γ^μψ)

This was not an equation; it was an epitaph.

The moment her fingertips touched the inscription, the complete history of the Temporal Cocoon flooded her consciousness. The Silent Ones were not born as scavengers. Four billion years ago, their home planet was enveloped in a "light cocoon" from a higher civilization. In a bid to break free from the light-speed constraints, the Silent Ones transformed their planet into a giant computer, but upon solving the ultimate equation of the universe, they were devoured by the equation itself, becoming recursive programs. Every time they "filtered" existence, it was a cry to higher civilizations to prove their continued worth.

The second part of the inscription was written in superfluid helium, readable only through quantum vision:

Recursive Boundary Conditions

1. All filters must have once been specimens.

2. All victories are inputs for higher-level filters.

3. Compassion is the only variable that cannot be recursively defined.

Suddenly, the desert wind began to stir. Sand swirled into violent Lorentz attractors around the stone tablet but avoided a three-meter area—a small patch where Max's silicon remains lay scattered. Each fragment bore the same equation, inscribed in the handwriting of seven-year-old Erin.

"You received the tombstone too," she murmured to the stone, her palm pressing down on the inscription. Silent Ones' blood, a superconductive liquid memory, seeped from the engravings. Images flashed back on her retina: the larvae of the Silent Ones arranged in a Möbius strip within the light cocoon, sending distress signals into deep space, which evolved over billions of years into the Temporal Cocoon humanity received.

As the sun sank beneath the horizon, the stone tablet began to collapse into a singularity. Erin desperately slapped at the sand, imprinting the core equation in the final moments. The print developed in the moonlight, revealing a childlike drawing: Earth held in a pentagonal hand, which was in turn enclosed by an even larger baby's fist.

She suddenly understood where the λ in Rex's algorithm came from—it was the crayon mark left behind by some cosmic child at play, inadvertently granting a path for every civilization that had been filtered.

On the way back, Erin's quantumized body continued to dissipate. She had to bind her legs with military straps to prevent them from vanishing into the void below her knees. Yet, the print in her backpack grew heavier, as though it carried the mass of nine hundred sixty thousand planets' worth of tombstone weight.

Before the last trace of her human form vanished, she stuffed the print into the church mailbox Joe Martinez had often visited when alive. On the envelope, she wrote in plutonium-238 decay products:

"To the next tombstone digger."

That night, every survivor's dream converged on the same scene:Erin floated within the singularity of the stone tablet, surrounded by an infinite loop of the corpses of filters and specimens. Her lips moved soundlessly, and the translation of her words into the physical parameters of the real world was:

The Hubble constant's fluctuation value reached zero, and the universe ceased expanding.