"Carter Catastrophe": The Math Formula That Foretells Human Demise

Humanity has been on a lengthy road to discover that we are not the centre of the universe, the galaxy, or even the Solar System since we evolved into a (semi) sentient species and began studying the cosmos.

Although disheartening for a selfish species, this insight has helped us uncover the true nature of our universe—or at least models that are more accurate. Even though the notion that the universe is homogeneous and isotropic in all directions has been contested, assuming it has led us to make predictions about the Friedmann–Lemaître–Robertson–Walker (FLRW) metric and the cosmic microwave background (CMB) that depict an expanding universe and are subsequently supported by astronomical observations.

Albert Stebbins of Fermilab told Phys.org in 2008 that "the Copernican principle is a cornerstone of most of astronomy, it is assumed without question, and plays an important role in many statistical tests for the viability of cosmological models."

"It is also a necessary consequence of the stronger assumption of the Cosmological Principle: namely, that not only do we not live in a special part of the universe, but there are no special parts of the universe – everything is the same everywhere (up to statistical variation)."

The idea that here and now is the same as there and now and here and then is the same as there and then makes it a very useful precept.

We may stare extremely far away and, considering the long light travel time, we are gazing at a remote region of the universe in the distant past. This allows us to view how the universe was in the past without having to look back in time at our current location. Their past and our past are identical in light of the Cosmological Principle.

In addition to this, there is the anthropic principle, which holds that only a universe that sustains life is suitable for conscious observers like ourselves. We shouldn't be shocked if we find ourselves observing a universe that supports life, as there may be a lot of other universes out there that don't. Or maybe the universe is different in different places.

Some philosophers and physicists believe that applying the Copernican and anthropic concepts to time may yield more insightful information. A smaller group of people think that this may be utilised to limit the amount of time that humanity has left to live.

For a short time, the argument was dubbed the "Carter catastrophe" because it was first put up by Australian astrophysicist Brandon Carter. The fundamental premise is that we shouldn't presume that we are in a unique location both in space and time. There will only ever be a certain number of people—let's say one trillion for convenience. In terms of statistics,

Assume that you were born at a random moment in human history rather than during a significant event like the beginning or the conclusion, as most ordinary onlookers would expect.

"We expect now to be situated randomly in this interval if there is nothing special about it, assuming that whatever we are measuring can only be observed in the period between begin and end. According to a 1993 paper by astrophysicist J. Richard Gott, the estimate future = (tend-now) = past = (now-begin) will overestimate future half the time and underestimate it the other half.

The probability P=0.95 that 0.02 The 95% confidence level is 1/39 past < future < 39tpast. In a similar vein, 1/3 past past <3 past (50 percent confidence level).

According to Gott, the length of time something has been visible in the past gives an approximate indication of how resilient it is to danger and disaster in the past as well as its likelihood of surviving into the future. You only need to suppose that your own place in time is random within that distribution of probable times for this equation to "work" (keep in mind that it is probabilistic and that numerous things could change it).

It is difficult to test the prediction that humanity will cease, unless we leave it to robots or the extremely intelligent mole people who will take over the planet after us. But Gott showed how it works by applying similar technique to a less dramatic event—the fall of the Berlin Wall. Gott visited Stonehenge and the Berlin Wall in 1969; they had been there for around 3,900 years and eight years, respectively.

If I were a random observer of the Wall, I would anticipate being at a random location throughout the period between "beginning" and "tend," which happens when the wall is destroyed or no one is left to observe it, whichever comes first.

Twenty years after the Wall fell, future = 2.5tpast, falling within the 95% confidence intervals that equation (1) anticipated. Stonehenge should be observable, as predicted by the same equation, and it is.

"Equation (1) was satisfied not because my visit somehow caused the demise of the USSR but simply because in hindsight we can now see that the timing of my visit was unremarkable," says Gott.

The fairly theatrical "Doomsday Argument" is a concept that has been employed to attempt and gauge where mankind could be on its journey to extinction. With a 95 percent confidence level, Gott, using a toy model and estimates of the number of humans born to date, places the estimated total number of humans yet to be born between 1.8 billion and 2.7 trillion (as of 1993).

Gott argues that we might not have much time left as a species based on birth and mortality statistics. In a little more than ten years, we might actually achieve 1.8 billion new births. We would still have to be on the unlucky side, but at this stage, we might be able to pass for randomly scattered observers and arrive up on Earth near the end, when the population has skyrocketed.

"Combining Nfuture <2.7 x 1012 (equation (10)) with the current rate of 145 million births per year we find tf<19,000 years unless the rate of births drops," Gott continues. " If we want to extend our lifespan to the maximum of 7.8 million years, We need the average birth rate to decrease by a factor greater than 400.

Birth rates, life expectancy, and other variables affect the calculations, as explained here. For instance, we might discover a scientific advancement in physics that drastically increases the risk of death for all parties (we're looking at you, nuclear warfare) or a medical discovery that greatly extends our lives.

In addition to this, observer classes have issues. Humans, for instance, have undergone extensive evolution. Do we need to factor in our forebears as well? Or what if humans and machines were to merge in the future? Do they qualify as observers for the purposes of this computation?

In summary, we wouldn't worry about it just yet, even if it would be an intriguing subject to research and a tool for looking at these kinds of issues. Most likely, extinction will occur long after you have finished your personal observation period.