The Last Five Seconds

One Second Is 437 Years

The sum is short enough to do on a napkin. The universe is about 13.8 billion years old; the Planck satellite's 2018 analysis puts it at 13.787 billion, give or take twenty million.^[3] A year contains 31,557,600 seconds. Divide the first number by the second and each tick of the cosmic clock is worth roughly 437 real years.

Sagan's own second was a little fatter. He was working with the fifteen-billion-year universe of his day, which made each second about 475 years, long enough to run from the end of the Middle Ages to his own day.^[1] The universe has since been measured more carefully and turned out to be younger than he thought, a compliment few of us receive after fifty.

One rule matters more than the arithmetic. Midnight on this calendar is not a deadline we are approaching. Midnight is the present moment, whenever you happen to be reading. The clock is always striking twelve, which means every figure in this essay is a measurement of how long ago something happened, and every one of them is quietly getting bigger.

Three Zooms to Find Ourselves

Here is the calendar drawn three times, each strip a magnification of the gold line at the bottom of the one before. Time runs downward. In the first strip the Sun does not switch on until the start of September,^[4] life appears about three weeks later, and the dinosaurs arrive on Christmas Day and are gone by breakfast on the 30th.^[2][5]

Look at the first strip and try to find yourself. You cannot. Everything from the Roman Empire to the phone in your pocket lives inside that gold line, and at this scale the line is a lie: I had to draw it three pixels tall so you could see it at all. It takes a magnification of more than six million to open the line into the second strip, and a further factor of five before the twentieth century stops being a smudge.

Eleven Moments, to the Millisecond

Pictures persuade; tables can be checked. Here are eleven moments with their positions on the evening of December 31. Writing gets a row even though it falls outside our five-second window, because it marks the beginning of everything we can actually read about.^[6] Sagan gave recorded history the last ten seconds of his slightly roomier calendar;^[1] on today's it gets about 12.

A few of those rows deserve a second look. Brahmagupta set down the arithmetic of zero in the year 628,^[7] which sounds ancient until you see that it is barely three seconds ago. Gutenberg, Newton and Einstein all fit inside the final second and a third.^[8] And the bottom two rows, the day CERN released the web's software for anyone to use^[9] and the day OpenAI released ChatGPT,^[10] are separated by 68 thousandths of a second.

Newton to ChatGPT is three-quarters of a second. The Scientific Revolution, the Industrial Revolution, two world wars and the digital age: one blink.

Listen to the Gaps, Not the Dots

The dots matter less than the distances between them. From Gutenberg to Newton is 237 years, or 0.54 of a cosmic second. From Newton to Einstein, 218 years: 0.50 seconds. From Einstein to the public web, 88 years: 0.20 seconds. From the web to ChatGPT, 30 years: 68 milliseconds. Each interval gave the world less time to absorb the last upheaval before the next one arrived.

I should be honest about the weakness in this. I chose the dots. Somebody else would choose the steam engine, the telegraph and penicillin, and get different gaps. Any list of milestones is partly a portrait of the person who made it, and mine is the list of a man who spent his life around computers. But try it with your own list. The direction survives nearly every honest selection, because the underlying facts are stubborn: more people, more literacy, more instruments, and each generation of tools used to build the next one faster.

My own life makes the point at my expense. I was born in 1958, which on this calendar is 0.16 seconds ago. In early 1985 I sat in a lecture hall in Arlington, Virginia, and heard that artificial intelligence would change everything within five years; that was 95 milliseconds ago, and the speaker was off by about 75 of them. The four years I spent building FedMine come to 9 milliseconds. The entire era of machines that can hold a conversation is, so far, no longer than the time it took one stubborn man to build one database.

This is the picture I wish I had drawn when I wrote The Clock Speed Problem. That essay argued that our machines run at silicon speed while our courts, legislatures and universities run at biological speed. The calendar puts a ruler on it. A Senate term is 14 milliseconds. Our institutions were built for a world in which the dots were whole seconds apart, and they are now being asked to respond inside a gap of 68 milliseconds that is still shrinking, as the machines begin, in a bounded but real way, to improve themselves.

Six Lines Worth Keeping

Every time I work through this arithmetic I end up with a few sentences I want to write on the wall. Here are the six that have survived my checking them.

1. For nearly all of 13.8 billion years, nothing on Earth could read a sentence. We have been literate for about twelve cosmic seconds, and machines learned to read in the last hundredth of one.
2. Newton and Einstein are half a second apart. Einstein and ChatGPT are barely a quarter of a second apart. We are not watching history accelerate from a safe distance. We are standing inside the flash.
3. Midnight on the Cosmic Calendar is not a deadline. It is the present tense. The clock strikes twelve every time you read this sentence.
4. The printing press and the atom bomb are little more than a second apart. The universe does not experience our history as a long story. It experiences it as a sudden noise.
5. ChatGPT arrived less than nine milliseconds ago. That is not enough time to decide what it means. It is also all the time there has been.
6. Every generation believes it lives at the hinge of history, and most have been wrong. I cannot prove we are the exception. I can only show you the spacing of the dots.

What the Calendar Cannot Tell You

A calendar measures when. It has nothing to say about what comes next, and I would distrust anyone who used this one as a prophecy. Accelerations end. Curves that look vertical have a habit of bending, and I have argued elsewhere that the silence of the galaxy may be telling us that clever species do not always get a long run. The diagram is evidence about our position, not a forecast of our direction.

Sagan did not live to see the last strip filled in. He died in December 1996, 68 milliseconds ago on his own calendar, three years after the web was set free and nearly sixty milliseconds before a machine could discuss Cosmos with you. I think about that often. He gave us the instrument, and it has gone on measuring without him.

What the instrument says is simple. Almost everything that has ever happened took a very long time, and almost everything that matters to us took no time at all. We are the species that arrived in the last few seconds and, in the last few thousandths of the last one, built something that learns. Whatever we decide to do about that, we will have to decide it at the speed of the clock we are actually living on, which is a good deal faster than the one we were raised to read.