The “Drake equation” is a well-known probabilistic model for predicting the number of alien civilizations in the galaxy, who are capable of interstellar communication.
In this article, I am going to take a brief look at the equation from the Christian perspective.
Frank Drake at the Green Bank Observatory in 1999. Image by the Observatory, CC-BY-NC-ND 2.0, here.
Frank Drake
The Drake equation was invented by Frank Drake (1930-2022), an American astrophysicist, who is recognized as the “founder of the search for extraterrestrial intelligence” (SETI).
In 1960 he started “Project Ozma” to search for extraterrestrial intelligence, by searching for radio transmissions around the 21 centimeter wavelength range at the National Radio Astronomy Observatory in Green Bank, USA.
During the next decades, he was heavily involved in SETI projects. In 1974, he sent the “Arecibo message”, a radio message containing basic information on the solar system, Earth and humanity, towards M13. M13 is a globular cluster (a cluster of stars) in the Milky Way. In 1984, Drake became the director of the SETI Institute, a non-profit dedicated to search for signs of extraterrestrial life. Of course, they had no success.
The equation
Drake described the equation in his 1965 paper “The Radio Search for Intelligent Extraterrestrial Life”.
Although the notation of the terms sometimes varies, he gives the equation as the following:
N = R*fpneflfifcL
(Note: the first term of the equation is R with a star as a subscript, due to the font, it looks very tiny)
“where
R* = the mean rate of star formation over the period in which the stars now possessing communicative civilizations were being formed. If we are typical, R* is about the mean rate of star formation 5 billion years ago;
fp = the fractions of stars which were formed at that epoch with planetary systems;
ne = the mean number of planets in each planetary system with environments permitting the development of life;
fl = the fraction of such planets on which life actually develops;
fi = the fraction of life-bearing planets on which intelligent life evolves;
fc = the fraction of planets bearing intelligent life which give rise to a communicative civilization;
L = the mean lifetime in the communicative state of such civilizations.”
The most glaring problem with equation is the term fl. It is the fraction of planets “on which life actually develops”. The idea that life can arise from non-living matter is complete garbage. It has never been proven neither in theory nor by experiments and it will never be proven.
In fact, there is a law of nature contradicting it: the law of biogenesis. It was discovered by Louis Pasteur in the 19th century and it is summed up in the Latin phrase “omne vivum ex vivo” (“all life comes from living things”). Evolutionists, however, believe that there was a time in Earth’s history where life arose from non-living things: when the first organisms arose from the “primordial soup”.
In 1961, Drake called together some of his colleagues and other scientists to discuss his idea for the equation. In this group were the science fiction author Carl Sagan and the astronomer Otto Struve. At this meeting, they proposed possible values for the different terms of the equation.
Drake saw the issue very optimistically. In his book, he wrote about one of his friends, Melvin Calvin, who won the Nobel Prize in Chemistry. He writes about an experiment Calvin did in the 1950s, where he managed to get a few amino acids by irradiating some basic chemicals, which was a precursor to the famous Miller experiment. Talking about the Miller experiment would be outside the scope of this article, but suffice it to say that he didn’t get anything remotely living, like a bacteria or a fungus, just a few chemicals.
Drake and his colleagues gave the fl factor a value of 1, meaning that on every planet suitable for live, life would “develop” (according to them). They also gave the next factor, fi, a value of 1, meaning that everywhere there is life, there is also intelligent life.
We can already substitute the number 0 into the fl factor of the Drake equation and get zero ET civilizations in our galaxy.
Other people have pointed out two further weaknesses with this theory. Even if we assume that life can “evolve” on another planet, they say that we still cannot be sure that aliens can get to a level of technological advancement high enough to communicate for a long period, because they are wiped out with nuclear war or some other disaster.
The Green Bank observatory. Image by the Observatory, CC-BY-NC-ND 2.0, here.
Others have also pointed out that the “lifetime” of a civilization might be very short. Drake thinks differently, referencing one of his colleagues: “The longer a detectable civilization lasts, the larger L becomes. What if a fraction of the few long-lived civilizations kept on an even keel for an extremely long time—a billion years, say? He figured out that if just 1 percent of alien civilizations had a lifetime of a billion years, then the value of L would make an enormous leap, from ten thousand to ten million.” (p. 68)
A one billion year old super-advanced civilization would have already made its presence known through EM waves which would have reached us by now. Again, there are no such signs.
in 1961, Drake assigned a value of 10000 to L.
Another issue is the second-to-last factor, the fraction of civilizations who possess the technology to communicate. To this factor, Drake and his colleagues assigned a value of one-fifth to one-tenth.
At the 1961 meeting, Drake and his colleagues assumed that multiplying the values of all the members of the equation, except the last one, gives one (the multiplication of 1 * 5 * 1 * 1 * 0.2 results in 1), “[t]he value of N thus hinged solely on the value of L. There was a new, streamlined form of the equation: N=L.” (p. 62)
Since Drake at the time thought that a civilization would last ten thousand years in a “communicative” state, he estimated that there were 10,000 such civilizations in the Milky Way.
In his 1965 paper he is more cautious, and writes: “If we are conservative, and accept L of the order of 103 to 104 yr, then perhaps one in 107 stars in the solar neighborhood presently possesses communicative species. The mean distance between them, and the distance any search method must then reach, is of the order of 300 parsec, or 1000 light years.”
Many people have recognized the connection between the Drake equation and the Fermi paradox and this gave rise to the Great Filter hypothesis. This hypothesis says that since there are no signs of intelligent civilizations anywhere in our galaxy, or the universe for that matter, some of the factors have to be either zero or very small.
Either way, the claim derived from the Drake equation, that there are various communicative alien civilizations, conflicts with the fact that we didn’t detect any alien communication.
Conclusion
The bottom line is this: the Drake equation as well as many other ideas and beliefs of alien believers run afoul of common sense and the observable facts. There is no proof at all for the existence of aliens. It doesn’t matter for alien believers that there are no alien radio signals. They just claim that they haven’t reached us yet or that we haven’t detected them yet.
I would like to end with a quote from Drake’s 1965 paper. “Our experience with Project Ozma showed that the constant acquisition of nothing but negative results can be discouraging. A scientist must have some flow of positive results, or his interest flags. Thus, any project aimed at the detection of intelligent extraterrestrial life should simultaneously conduct more conventional research.” Perhaps the “constant acquisition of nothing but negative results” could be a clue to people searching for ET life that there is none.