How long do humans have left on Earth?:New research says that humanity could vanish in 17,000 years; here’s how

Can mathematics really predict when humanity will disappear? It sounds like science fiction, but some mathematicians believe probability can offer clues about how long humans are likely to survive. Their calculation doesn’t predict how humanity will end: it could be climate change, a global pandemic, nuclear war, or something completely unexpected. Instead, it estimates when our species might reach its end. One famous mathematical theory suggests that, with 95% confidence, humans are unlikely to survive for more than 17,100 years from now. But how did researchers arrive at such a specific number? It starts with a simple idea The prediction comes from a theory known as the Doomsday Argument, first proposed by astrophysicist Brandon Carter in 1983. The argument is based on the Copernican Principle, which says humans are not in a special position in the universe. Just as Earth isn’t the center of the universe, our place in human history is also assumed to be ordinary not unusually early or unusually late. In other words, you should think of yourself as a random human born somewhere in humanity’s entire timeline. Imagine humanity as one long timeline Picture a timeline that starts with the first human ever born and ends with the last human who will ever exist. Scientists estimate that around 117 billion people have lived on Earth so far. Let’s call this number x. Now imagine the timeline contains every human who will ever be born. That total number is represented by N. If your place on this timeline is completely random, then there’s a 95% chance that you’re not among the first 5% of all humans. That idea can be written as a simple mathematical equation: x > 0.05N This equation is the foundation of the entire prediction. The math behind this At first glance, the equation may look confusing, but the calculation is surprisingly simple. Here, The equation says: Now multiply both sides by 20: Replace x with 117 billion: This means that, according to the Doomsday Argument, there is a 95% probability that the total number of humans who will ever live will be less than 2.34 trillion. That estimate becomes the basis for predicting how much time humanity may have left. Why researchers think this makes sense? A simple thought experiment helps explain the logic. Imagine there are two sealed boxes. Someone randomly hands you ball number 4, but you don’t know which box it came from. Most people would guess it came from the smaller box because drawing ball number 4 is much more likely there than from a box containing 100,000 balls. The Doomsday Argument applies the same reasoning to humanity. If around 117 billion people have already lived, it’s statistically more likely that humanity belongs to a “smaller box” where only a few hundred billion more people are yet to be born than to a future where trillions upon trillions of humans spread across galaxies for millions of years. So where does the 17,100-year figure come from? Once mathematicians estimated that no more than 2.34 trillion people are likely to exist, they looked at current birth rates. For roughly the last 40 years, around 130 million babies have been born worldwide every year. Although birth rates are falling in many countries, the global population is still increasing. If births continue at around today’s pace, it would take approximately 17,100 years for humanity to reach the estimated limit of 2.34 trillion people. The exact number could change if birth rates rise or fall significantly, but the estimate remains in the same general range. Not everyone buys the theory Despite its popularity, the Doomsday Argument is highly controversial. Many scientists argue that it relies on assumptions that may not hold true. For example, humans could eventually settle on other planets or even spread across the galaxy, allowing countless more people to be born than the theory predicts. Others say our place in history may not be random at all. Since advanced science and mathematics have only recently emerged, humanity could still be in the early stages of its overall journey. Some critics also argue that focusing only on humans ignores the much bigger picture of all life on Earth, making the calculation less meaningful. A mathematical thought experiment – not a prophecy The Doomsday Argument is not a prediction that humanity will disappear in exactly 17,100 years. It is simply a statistical model based on probability and assumptions about our place in history. There is no evidence that such an event is destined to happen, nor does the theory explain what might cause humanity’s end.