Notes toward an unfinished universe — Elior Voss

The Last Photon

It left the photosphere of a star that no one had named, in a galaxy that would not be catalogued for another four billion years, and it did not know it was last. Photons do not keep roll calls. They are born in a crowd and they leave without looking back.

The star had been burning its hydrogen with the unhurried competence of a civil servant. Then the hydrogen ran out, as hydrogen does. Helium followed. The core folded in on itself with a kind of professional embarrassment, and the outer layers were thrown into the dark like furniture from a window.

Most of the light that left that night would wander until it hit something: dust, a planet, the inside of an eye that had not been invented yet. This one did not. It was aimed—if aimed is the word for an accident with a direction—into a corridor of nothing so clean that even the vacuum seemed newly swept.

Time, for a photon, is a rumor other people tell. From its own seat there is no interval between departure and arrival. The universe happens all at once, or not at all. So the last photon did not experience the years. It experienced a single fact: I am going.

On a wet Tuesday in a city that would later call itself by several names, a woman named Ilaria stepped onto a balcony to smoke the cigarette she had sworn she would not buy. She had been grading papers. The papers were about metaphors for time. She was tired of metaphors for time. She wanted time to be a kitchen clock and to shut up.

She looked up because the smoke went that way. She did not see the photon. No one sees a single photon unless they have built a machine for the purpose and even then they see a click, a number, a small religious event in a detector. What she saw was a sky with no particular news in it. She finished the cigarette. She went back inside. She wrote in the margin of a student’s essay: time is not a river. Rivers know where they are going.

The photon continued. Galaxies drifted. A civilization on a wet world invented glass, then lenses, then the habit of pointing both at the dark and asking the dark to explain itself. The photon missed all of that by a margin so thin it would have been comic if anyone had been keeping score.

There is a place—though place is generous—where the expansion of spacetime stretches a wavelength past the point of meaning. Redshift becomes a kind of forgetting. The last photon did not die. Dying is for things that had a body to surrender. It simply became too long to be light. It became a footnote in a field. It became the idea of a journey that no longer had a traveler.

Ilaria died in a hospital that smelled like lemons and compromise. Her daughter kept the essay with the margin note and did not know what to do with it. She put it in a drawer with rubber bands and a broken watch. Years later a grandchild found it and thought: time is not a river. All right. Then what is it.

The grandchild became an astronomer, which is a way of refusing to let the question sit in a drawer. She spent a winter on a mountain, watching a patch of sky so empty it made the instruments nervous. She was not looking for the last photon. She was looking for anything that still had the decency to arrive.

Nothing in that patch arrived that she could publish. She published anyway: an upper limit, a careful absence, a paper that said, in the dialect of her trade, we looked, and the looking has a shape.

That is as close as the last photon ever came to being met.

Somewhere that is not a somewhere, the stretched remnant of it is still going, if going is the word for a thing that has forgotten how to be a wave. The universe, which does not keep roll calls either, does not notice the difference.

The difference is ours. We are the species that names the one that does not arrive, and then goes back to the balcony, and lights another cigarette we promised we would not buy, and looks up anyway.