When physics intersects with philosophy, bizarre things are born. This is the case of an equation that seems to have managed to predict the fall of the Berlin Wall and the longevity of Stonehenge, and which estimates that we will disappear somewhere between… tgift e tfim.
Since we became an intelligent species and began studying the Cosmos, Humanity has embarked on a long journey of realizing that we are not the center of the universe, the galaxy or even the Solar System.
Although disappointing for an egocentric species, this realization has led us to discoveries about the true nature of our Universe, or at least to models closer to reality, he says. James Feltonauthor of “Assholes:The Dead People You Should Be Mad At“, no .
Although there are challenges to the idea that the universe is homogeneous and isotropic in all directions, assuming that it is allowed us to make predictions about the cosmic microwave background radiation (CMB) and on the metric of Friedmann–Lemaître–Robertson–Walker (FLRW), which describe an expanding universe, later confirmed by astronomical observations.
“O Copernican Principle — the idea that the Earth does not have a special or privileged position in the universe — is a cornerstone of most astronomy, is assumed without question and plays an important role in many statistical tests on the viability of cosmological models”, explained in 2008 the physicist Albert Stebbinsfrom Fermilab, to .
This principle “is also a necessary consequence the broader assumption of the Cosmological Principle: that is, 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, even statistical variations”, highlighted Stebbins.
“It is an extremely useful principle, as it implies that here and now is the same there and now, and here and then is the same as there and then“, says the physicist.
“We don’t need to look back in time in our location to understand what the universe was like in the past; we can just look very farand given the time it takes for light to arrive, we are observing a distant part of the universe in the distant past. Considering the Cosmological Principle, this past is just like our past“, adds Stebbins.
Furthermore, there is the Anthropic Principle: the idea that conscious observers like us can only exist in a universe that supports life.
Maybe there are many universes that do not support lifeand we shouldn’t be surprised to find ourselves observing a universe that supports it. Or maybe the universe isn’t the same everywhere.
According to several physicists and philosophers, there may be useful information to be drawn from the application of the Copernican and Anthropic principles to time. Some believe this could be used to put limits on the time that humanity has left.
This argument, first put forward by Australian astrophysicist Brandon Carter in a published in 1983 in Philosophical Transactionswhich temporarily gained the name “Carter catastrophe”.
The basic idea is that we should not assume that we are in a special region in time as well as in space. Throughout all the time since Humanity existed until its end, there will be a finite number of humans — say, for simplicity, a total of 1 billion of humans.
Statistically, we must assume that we were born at a random point in the history of Humanity, and not at a special moment, like the beginning or the end, where most typical observers would be.
“Assuming that what we are measuring can only be observed in the interval between tstart e tfimif there is nothing special at the current moment, we hope that tgift is randomly located in that interval,” wrote the astrophysicist J. Richard Gott in a paper on this topic published in the magazine Nature em 1993.
The estimate tfuture = (tfim – tgift) = tpast = (tgift – tstart) half the time it will overestimate tfutureand underestimate the other half”, explains Gott.
According to Gott, if r1 = (tgift – tstart) / (tfim – tstart) is a random number uniformly distributed between 0 and 1, then there is a probability P = 0.95 that 0,025 < r1 < 0,975.
That is, with a 95% confidence level:
1/39 x tpast < tfuture < 39 x tpast
Similarly, with 50% confidence:
1/3 x tpast < tfuture < 3 x tpast
According to Gott, the length of time something has been observable in the past provides a rough guide to your robustness in the face of dangers and catastrophesbut also your probability of surviving in the future.
For this equation to “work”, taking into account that it is a probabilistic and there are many variables that can change itall that is necessary is to assume that your own position in time is random within this distribution of possible times.
Predicting the end of humanity is not something that can be easily testedunless the conclusion is left to robots or the hyperintelligent species of creatures that will inherit the Earth when we are no longer here.
But, to demonstrate its operation, Gott applied this analysis to a less dramatic event, the fall of the Berlin Wall. In 1969, Gott visited the Berlin Wall and Stonehenge, which had existed for approximately 8 and 3,900 years, respectively.
“Assuming that I am a random observer of the WallI hope to be located randomly no time between youstart e tfim — whereas tfim occurs when the wall is destroyed or when there are no more visitors to observe it, whichever happens first”, explains Gott.
“The Wall fell 20 years later, which gives tfuture = 2,5 x tpastwithin the 95% confidence limits predicted by the equation”, notes the astrophysicist.
“The equation was satisfied not because my visit had somehow caused the fall of the USSR, but simply because, in retrospect, we can now see that the timing of my visit was not special”, concludes Gott.
The same equation predicts that Stonehenge should be observable — and in fact it is.
The idea of Richard Gott, which eventually became known as the dramatic something “Doomsday Argument”, has been used to try to understand where humanity can be located on its path to non-existence.
Using a simplified model and estimates of the number of humans born in 1993, when the world population stood at around 5.5 billion, Gott estimated that the expected total number of humans yet to be born is located between 1.8 billion and 2.7 billionwith a confidence level of 95%.
Analyzing birth and death rates, Gott suggested at the time that he could we don’t have much time left as a species.
In fact, given that the world population is currently 8.2 billion people, since Gott formulated his theory, 2.7 billion have been born of humans, that is, we have already exceeded the minimum limit of unborn humans predicted in the North American astrophysicist’s equation.
Fortunately, the maximum number of births is a comfortably very high number, which means that if humanity ended these days we would have been on the “unlucky” side of the distribution they Good.
But at this point, we could frame ourselves as randomly distributed observers, finding ourselves on Earth when the population explodes, but very close to the end.
“Combining Nfuture < 2,7 x 10¹² with the current rate of 145 million births per year, we find tfim < 19,000 yearsunless the birth rate decreases,” adds Gott.
Like this, if we want to prolong our survival up to the maximum limit of 7.8 million years, it would be necessary for the average birth rate to decrease by a factor greater than 400, highlights the astrophysicist.
All these equations are subject to variable factorssuch as birth rates, average life expectancy, etc.
For example, we could find a medical breakthrough that allows us to live much longer, or, in the opposite field, an advance in physics that makes life significantly more dangerous for everyone. Or go through a nuclear war…
Furthermore, There are problems with the “observer classes”. For example, humans have evolved over a long time. Should our predecessors be included in the calculation? What if in the future we merge with machines? Should these entities be considered observers in this equation?
While this is an interesting philosophical topic to explore, there is no reason to worry just yet. The inevitable extinction of humanity will eventually occur, algures between tgift e tfim — and this will, very, very likely, be long after your observation time has ended.
