Since the 1990s, scientists have discovered new exoplanets outside our solar system every year. Specifically, 3,453 extrasolar planets , according to NASA data from February 2017. Therefore, it is not surprising that we try to imagine how many of them, discovered or not, have extraterrestrial life . What’s more, how much of that life will be smart enough to communicate with the outside.
In 1961, Dr. Frank Drake decided to develop an equation capable of calculating the number of, not only the civilizations that exist, but those that can also communicate with ours , in the known universe. Statistics allows, taking into account a series of variables , to find a number N that would give us the answer.
The Drake equation is described as follows: N = R • fp • ne • fl • fi • fc • L.
A : number of stars capable of hosting planets , that is, other stars like our Sun.
fp : number of those stars that have planetary systems , like ours.
ne : the average number of Earth-like planets that could be in those systems. That is, terrestrial planets in the habitable zone of their star (not too close and not too far).
fi : the number of planets on which intelligent life develops.
fc : the number of planets with intelligent life and that is also capable of communicating throughout the universe (with technology such as radio waves or electromagnetism).
L : the time that a civilization like this is able to survive on a planet.
If we take into account that there are between 200 and 400 billion stars in the Milky Way , Drake’s estimates concluded that the probability of finding an intelligent civilization communicating is 0.00000003%. Although it may not seem like it, it is a rather optimistic number: of up to 10 detectable civilizations in our galaxy alone.
However, despite the fact that the equation is well formulated, the fractions to multiply depend a lot on the estimates of whoever performs the operation. It is practically impossible to determine an approximation of some factors , such as the number of planets with intelligent life, or the number of civilizations with technology to communicate. Therefore, the interest of the equation lies in its nature, its elaboration , rather than in a result that can be applied in practice.
For many, Drake’s estimates are too optimistic , and other scientists have repeated his equation with somewhat more “realistic” estimates. In the worst case, N = 1, that is, we are the only civilization with interstellar communication capacity that exists in the universe. But this figure, in turn, may be too catastrophic, or perhaps self-centered. In any case, this time, mathematics cannot give us the answer.
While the fact that life of some kind exists on other planets is quite likely , (and, although it has not been proven, scientists take it for granted) the magnitude of the universe makes it incredibly difficult to predict whether other civilizations with technology exist. ; and, if it exists, that the space-time fabric makes us coexist on the same plane, that allows communication. Until we happen upon some clue of intelligent life roaming our cosmic neighborhood , there will be no sure way to find out if, indeed, we are not the only ones wondering if there is someone else up there, asking the same question.
