For a date that has been sitting in a scientific paper for more than six decades, November 13, 2026, is suddenly getting an unusual amount of attention. The date falls on a Friday, just as it did when it was first calculated, and the old paper attached an alarming name to it: “Doomsday.” But the mathematics behind that date tells a very different story from the one now circulating online.
The calculation appeared in Science in 1960 in a paper by Heinz von Foerster, Patricia M. Mora and Lawrence W. Amiot. Its full title was “Doomsday: Friday, 13 November, A.D. 2026.” The three researchers were members of the Department of Electrical Engineering at the University of Illinois in Urbana.
They looked at historical estimates of world population and fitted those figures to a mathematical model. When they extended the pattern into the future, the equation reached a point in 2026 where the calculated population would approach infinity.
That sounds far more frightening than what the calculation actually meant. The researchers were not forecasting an asteroid strike, a nuclear war, a pandemic or the physical destruction of Earth. They were looking at what would happen if human population kept growing at the accelerating rate seen in their historical data.
The important part was the condition attached to the calculation. The paper said the population would approach infinity if it continued growing as it had grown during the previous two millennia. In other words, the result depended on the growth pattern continuing unchanged. The “Doomsday” point was a mathematical singularity. It was the point where the equation stopped giving a realistic description of population.
The distinction matters because the world did not continue along that curve.
Population growth changed dramatically after the paper was published. Fertility rates began falling in many parts of the world. Families became smaller. Life expectancy increased and child mortality declined. Education and access to family planning also changed the way populations grew.
The old equation could not account for all of those changes because it was based on a historical pattern. Once that pattern changed, the projection changed with it.
There is an almost striking contrast between the old calculation and the picture provided by today’s demographic data. The United Nations estimates that the world’s population was about 8.2 billion in 2024.
It expects the number to keep rising for several more decades and reach about 10.3 billion in the mid-2080s. After that, the global population is projected to gradually decline.That is nowhere near an infinite population.
The UN also reports that global fertility has fallen considerably. Women worldwide are now having about one child fewer on average than they did around 1990. More than half of countries and areas have fertility below the roughly 2.1 births per woman level generally associated with long-term population replacement without migration.
The change is especially clear in countries that have already passed their population peak. China, Germany, Japan and Russia are among the countries and areas whose populations have already peaked, according to the UN. At the same time, countries including India, Indonesia, Nigeria, Pakistan and the United States are expected to keep growing for longer.
So why November 13?
The answer is buried in the mathematics. The researchers calculated a point at which their population curve would become infinite. Their result was around 2026.87, which corresponds to November 13, 2026.
There was also a remarkable coincidence behind the date. November 13 was von Foerster’s birthday. He was born in Vienna on November 13, 1911. The fact that his calculated date landed on his own birthday, and that it was a Friday the 13th, made the title far more memorable.
The paper’s language was deliberately dramatic. It warned that humanity could eventually be “squeezed to death” rather than starved as population pressure increased. But von Foerster did not actually believe that people would reproduce until the population became literally infinite. His own university later described the famous formula as a tongue-in-cheek “doomsday formula.”
That detail is often missing from the viral version of the story.
The same thing happens with the mathematics. “Scientists predicted the end of the world on November 13, 2026” is a much easier story to share than the real explanation.
The 1960 researchers had taken historical population figures and extended a particular mathematical curve. They were not predicting that Earth would suddenly become uninhabitable on a specific Friday.
There were also problems with treating such a long-term extrapolation as a literal forecast. Historical population figures were estimates, especially for periods thousands of years ago. Human population is also affected by biological and social limits that a simple growth curve cannot fully capture. And the real-world trend eventually moved away from the model.
A 2025 peer-reviewed analysis revisited the old population model using a much larger set of historical population data. The researchers found that the original mathematical singularity does not translate into an infinite human population. Instead, modern evidence points toward population reaching a peak and then declining.
That fits much more closely with the latest UN projections.
There is no current scientific evidence that November 13, 2026, will mark the end of humanity or the world. No recognised demographic projection puts a population catastrophe on that date. The available evidence points in the opposite direction: global population growth is slowing and the world is moving toward a population peak later this century.
The old paper is still worth revisiting because the question behind it has not disappeared. How far can a trend continue before the conditions behind it change?
In 1960, the researchers used the information available to them and followed the population curve forward. The curve produced a remarkable date. More than six decades later, the date has become a piece of internet folklore.
November 13, 2026, will arrive like any other Friday. The population will not suddenly become infinite, and there is no scientific reason to treat the day as humanity’s final one.
The interesting part of the story is not that scientists predicted the end of the world. They didn’t.
They showed how an alarming conclusion can appear when a mathematical trend is extended far beyond the period in which it was measured and how quickly that mathematical result can turn into a prophecy once the original warning is forgotten.
