Climate collapse, epidemic, nuclear war, solar storm, asteroid, gamma-ray burst… it is not hard to imagine a planetary-scale event that ends humanity, but what drives experts crazy is not the “how”, but the “when”.
Doomsday Argument: How Long Until the End of Humanity?
That brings us to the so-called Doomsday Argument, a mathematical formula that seeks to predict the end of humanity. Depending on who interprets it, the argument yields results as close as 760 years, while its detractors place it on par with pseudoscience and quackery.
Because no, we cannot see the future. And to tell the truth, I think that is a good thing. Warnings about perfect predictions are very numerous, and no matter how solid our intentions, the risk of creating a worse fate is very great. However, we have never stopped trying. There are many things humanity as a whole wants to know, and one of them… is its end.
Our planet is finite, as is the rest of the solar system and our own mother star. But it is likely that the end of humanity will come much earlier. According to an equation… in the next 760 years. Welcome to the Doomsday Argument.
In extremely relaxed terms, the exercise proposes that the longevity of a thing (from a product on a shelf to the human species itself) can be estimated with some precision from its history.
And speaking of history, to understand this we must go back to 1969, the year in which J. Richard Gott III, today an astrophysicist at Princeton University, was enjoying the European summer.
When visiting the Berlin Wall, Gott told a friend that the Wall had between 2.67 and 24 years of life left. Its opening was ordered in 1989, 20 years later than when he made his calculation.
Gott's prediction takes as its reference the Copernican Principle, which basically indicates that the Earth and humans are nothing special or central. So the astrophysicist estimated that the Wall's duration would be between one third and three times its past duration.
When Gott visited the Wall, it had already been there for eight years, therefore, (8/3) - (8x3), 2.67 - 24 years, with a 50 percent probability. The difference is that this method allows us to reach whatever level of confidence we desire.
What about 95 percent? That way, the prediction becomes wider, 1/39 to 39 times, which gives us between 0.21 and 312 years. Much less impressive... but technically correct.
In June 1993, Gott applied this equation to the duration of humanity. With 200,000 years (average) of Homo sapiens, the relationship reveals a minimum additional duration (at 95%) of 5,128 years, and a maximum of 7.8 million years.
In contrast, if we extend it to the total number of humans that will be born in history, the plot becomes more pessimistic. It is estimated that about 100 billion humans have lived so far.
If the most likely thing is that we are halfway to extinction (the essence of the argument), with 130 million births per year, we get a 50 percent chance that we have just over 760 years left.
Refutations? Several, and at different levels. The Doomsday Argument is extremely controversial, and it has been analyzed to exhaustion.
The one closest to us mortals is that the great events that cause mass extinctions are actually very rare, with more than a million years between one and another, therefore humanity should be safe for the next 100,000 years, at least.
Source: Wikipedia
