No one knew how long Catherine Malone had been missing. Her absence was reported to the police after three weeks of unpaid rent, but neighbors admitted they hadn’t known that the apartment was occupied. “She kept to herself,” said the landlord.
The universe does not think in hours, days. There is no measure of universal time. Humans count one moment after the other. Consecutive time. But a vibrating cesium atom doesn’t know how many times it’s shuddered. A sun doesn’t know how long its burned. Time is dependent on the consciousness of the observer, and without someone to draw demarcations between the seconds, time becomes an unlabeled, unmeasured stream.
So what clock must a time machine be set by?
The landlord unlocked the apartment himself, but found no sign of his tenant. Half-read books and half-filled notebooks rested open upon every table, and a mostly-empty pizza box had attracted a halo of flies. The bed was unmade, and the dishes were filthy. The wooden floor was littered with crumpled clothing.
Does time attach itself to an object and move with that object? Specifically, would a time machine set for three days prior return the traveler to the room she departed from, or to the naked void of space left in the wake of the moving Earth? Can there be universal latitude and longitude in an expanding universe, or is that another human construction? In the latter scenario, how could a machine be set to return a traveler to the Earth?
The police could find no next of kin, and although a brief investigation suggested abduction, that theory was ultimately disregarded. “She probably just picked up and left,” said an officer in an off-the-record conversation. “People do that sometimes. Move to a different state to start over.”
Assuming that the problems of the initial leap could be easily solved, the biggest problem becomes the return journey. A person’s presence out of their own time would certainly change their future, so how could they return to the world they’d left? If an oddity like time travel were to spark the creation of an alternate timeline, how could the machine be set to return to the timeline of origin? Could a chronological beacon be constructed, like a lighthouse through time?
The case remained open, long after the apartment had been cleared and rented to another tenant. No next of kin appeared, and the woman’s belongings were donated to a nearby shelter. After a decade, the files on open but unsolved cases were moved to the basement of the precinct, where they rested for almost half a century before a flood turned the papers soggy and rusted the ancient hard drives. “We’re working to restore the old documents,” a representative said during a press conference, shortly before ordering the boxes to be returned to the basement. “These things are sixty years old,” he said to a coworker. “No one remembers them anyways.”