The bather lived in a 1920s house grotesquely rendered into apartment units. As usual during his bath, he stared at the painted pipes in the corners. They wormed through holes cut in ancient wood. The oldness of the thick walls and window frames had a touch of charm and a barrel of ruggedness. Everything in the bathroom remind him that people hoarded houses too long, and not just the junk inside the houses.
A scientific push began, in fact, to build materials the clingy types could keep forever. One eccentric billionaire recently paid tens of millions for such an endeavor. He gathered scientists to produce a substance so dense and indestructible, so stable and insoluble, that it would last for eons. The sun and Earth could throw everything they had upon this material, and it would retain every molecule.
News spread of this. The most imaginative article writers, the bather recalled, described a scenario of alien explorers finding a long-cold Earth. The future travelers would find only silt and stone, mud and dirty ice. All mankind's thickest vaults will have corroded, crushed, or melted. They'd spill their sacred holdings and all man's symbols into oceans or mudslides. The black tsunamis and flamethrower jet streams of one natural apocalypse or another would spread our constructs thin. The planet's death throes will churn all trinkets in a perennial tornado. Everything would bust into a glittery soil, then dull itself in a dark sandstorm.
But in that blend of atoms, the alien archaeologists still might find the one surviving object the scientists had built. It would hold together in the lava baths and ash storms. The billionaire, rapt by such far-fetched internet stories, ordered his material forged into a disk. It encased an atomic battery and transmitter, protected for eternity. Every eight days, the disk emits a complex wave signal. The pulse will continue for billions of years.
The hypothetical aliens, then, could detect the signal and locate the everlasting disk. They would send their machines through the igneous rock and frozen sludge to obtain the one remnant of man. Wherever the artifact had tossed or whichever elements submerged it, the disk would cry for discovery.
Then they would know. The aliens, by whatever fluke of their existence and choice of travels, could hold that one token and marvel at man's ingenuity. The disk will serve as the final punctuation mark to prove humans lived at all.
The billionaire just needed a symbol, a sign or two of humanity's greatness. He sought ideas from around the world. Contests arose, official or otherwise, all striving for the design most representative of man's progress. Many pleaded for religious symbols. But the aliens, if their fantastic arrival happens, would fail to comprehend such markings. They'd require contexts and historical records.
Other artists suggested that great poems or historical figures' names should get stamped on the disk. But again, each side had too little surface area for a picture key to decipher language. Some contestants argued for etching microscopic letters on the disk's edge. This, however, would cost more money than the billionaire wished to spend. Furthermore, the letters would not even appear as visible graininess. The curious aliens would grasp a seemingly flat scrap of metal. Perhaps they would face expenses of their own trying to extract dirt and metals hardened into the imperceptible letter groves. Maybe they'd give up, fearful of damaging the artifact and losing information.
No, the aliens needed a punch in the eyes. A symbol, a big one, should startle them into centuries of obsession with long-gone man. The world voted, and the majority chose a simple design: a man and woman holding hands, a simple depiction of love. Inspired by famous statues and the outline drawings on the Pioneer plaques, the design took dozens of leading artists to perfect. The gifted, the prolific, the poor, and even the blind left a mark on the final computerized engraving.
The quest began to design the opposite side. Mankind had chosen heads, but tails needed immortalizing too. Some wanted a baby's face on one side and an old man's on the opposite. Others demanded a beautiful landscape that encapsulated Earth in her prime including sea, sunset, mountains and trees. Other leading concepts included cityscapes, simple tools, or a cluster of plant and animal genera—all brilliant, and potentially, instantly understandable to any alien professor.
But the billionaire settled on a design he created himself: his face, of course. It would do on both sides.