Find Orion on a winter night and look at the red star at the hunter's shoulder. That is Betelgeuse, roughly five hundred and fifty light years away, which means the light entering your eye left the star somewhere in the fifteenth century, before Columbus sailed. What you see tonight is a report, sent five centuries ago, arriving now.
Now find the faint smudge in Andromeda, the one object outside our galaxy visible to the naked eye. Its light is two and a half million years old. It left before there were humans to see it. Every photon that lands on your retina from that galaxy set out before anyone on Earth had lit a fire.
Astronomers call this lookback time. The further away a thing is, the older the picture of it you receive. The night sky is a collage of thousands of different pasts, some minutes old, some older than our species, arranged on one dome so that they look simultaneous.
THE STAR THAT IS ALREADY GONE
Betelgeuse is a red supergiant near the end of its life. At some point in the next hundred thousand years it will collapse and explode, and for a few weeks it will be bright enough to see in daylight. In late 2019 it dimmed to about a third of its usual brightness and, for a few months, people who knew what that could mean checked the sky every evening. It turned out to be a cloud of dust. The star is still there.
Probably. Nobody can be sure. If Betelgeuse exploded four hundred years ago, the news is still in transit, and Orion's shoulder will look exactly as it does tonight until the day the light of the explosion arrives. A star can be dead and still on the chart. The chart shows the light that reached it, which is all any chart has ever shown.
This is true of every star on every atlas ever drawn. Bayer's Uranometria of 1603 is a map of where light was in 1603, sent from places and times that had nothing to do with each other. Hipparchus' catalogue, recovered from under the prayers of a medieval monk, records positions of light that left its sources centuries before he was born. Every star chart in history is a record of arrivals.
THE FUNCTION YOU DELETED IN 2021
Open a contribution graph from a developer with ten years on it and pick a bright week in 2019.
The function written that week was deleted in 2021, in a refactor that made it unnecessary. The service that took the whole spring was replaced by a vendor in a single afternoon in 2023. The startup was acquired and its repository archived, read-only, a tombstone with the code still inside. The migration script ran once and was never needed again. The feature was built, shipped, used by a hundred thousand people, and removed when the product changed direction.
The person who wrote those commits used a language you have since abandoned and a framework you now recommend against. They named things badly. They did not know what you know. They had not yet had the argument that changed how you structure a service, had not yet been through the outage that taught you to distrust the cache, had not yet read the book. They were, in every way that matters to the work, someone else.
And the star is still there. On the graph, and on any atlas drawn from it, the bright week in 2019 is exactly as bright as it was the day it happened. Its light left a source that no longer exists, from a person who no longer exists in that form, and it is still arriving.
A THOUSAND PASTS AT ONCE
Most people, seeing their graph rendered as a sky for the first time, read it as a picture of their career. It is more precise to say it is a picture of arrivals. Each star is light from a different moment, sent by a slightly different person, out of a codebase that has since changed or vanished, all landing on one sheet so that they look like a single continuous thing.
That is what a career is, seen from outside. A collage of pasts that never coexisted. The self who wrote the 2016 commits never met the self who wrote the 2024 ones. They share a username and little else: the tools have changed, the opinions have changed, and most of the code the earlier self wrote, the later self has since removed.
The graph holds them together the way the sky holds Betelgeuse and Andromeda together. Different distances, different ages, one dome.
WHAT THE CHART CANNOT KEEP
One honest limit. If you delete a repository, GitHub removes its contributions from your graph. The star goes out at once, with no delay in transit. Archived repositories keep their stars. Renamed and transferred ones keep them. Code deleted from inside a living repository, which is the fate of nearly all code, keeps every star it ever earned, because the commit happened and the graph records that it happened. The only way to lose the light is to destroy the source and the record together. The full rules for what the graph counts and what it drops are in our explainer.
We mention this because a print made from a graph is only as complete as the graph, and we would rather say so than let anyone believe the atlas can see light that has been put out at both ends.
FIXING THE LIGHT
A photograph of the night sky is a way of stopping the arrivals. The light has been travelling for a thousand years and lands, finally, on a plate, and stays there. Astronomers before the photographic era had no such thing. They drew what they saw, by hand, and the drawing outlasted the seeing.
A print is the same act. The graph will keep changing. The years will roll off the default view. Code will keep being deleted, repositories archived, the person who made the commits keep turning into someone else. A print fixes the light where it is on the day it is made: every star that has arrived so far, from every past that sent one, held still on a sheet of archival paper that does not know or care whether the source still exists.
It does not make the code come back. Nothing does. What it keeps is the fact that the light was sent, and the shape it made when it landed.
The code is gone. The light is still arriving.
Fix the light where it is. Enter your GitHub username at codexstellarum.com and preview your atlas - free to try, prints from £25.