NOVEMBER 29, 2020 – Late last night, after hauling out the garbage I stopped in the middle of the driveway and gazed at Orion and his entourage. I then did something unscientific: I made “a wish upon a star.” I then did something more scientific: I pondered the compound odds of (a) “intelligent” life existing “out there somewhere”; (b) our connecting with it; and (c) mutual comprehension between us and “them.”
Without a frame of reference, I went inside to study the question. My opening source: The Total Skywatcher’s Manual, published by “Astronomical Society of the Pacific.”
First, I learned that the scientific discipline around the question at hand is called “astrobiology” and that one of its founders was a guy named Frank Drake. It turns out, however, that The Total Skywatcher’s Manual didn’t provide the total scoop on our man Drake. For a fuller story on the guy, I consulted Wikipedia, where I learned lots about him. (https://en.wikipedia.org/wiki/Frank_Drake)
The thing to remember about Drake is the “Drake Equation,” a mathematical expression of the probability that communicative, non-earthlings now exist in our galaxy—the Milky Way. The formula looks like this: N = N[stars] fp ne fl fi fc fc. In layperson’s English, that reads, “The number of communicative civilizations in existence—right now—in the Milky Way equals the number of stars in the galaxy times the fraction of those stars with at least one planet times the fraction of planets that have life-supporting conditions (primarily liquid water) times the fraction of planets where life of any kind has developed times the fraction of planets where life has evolved to an “intelligent” stage times the fraction of planets where the “intelligent” life has developed detectable communication technology times the fraction of planets where life with detectable “listening” technology is also able and willing to broadcast across vast inter-stellar distances.”
The equation has no solution, of course, but it’s a good exercise in perspective to consider each component, to-wit:
Total stars in galaxy: 100 to 500 billion.
Stars with at least one planet: probably all.
Planets supporting life: who knows; within our own solar system, the fraction is as high as two-thirds
Planets where life developed: wild guess; within our own solar system, at least one in nine—or is it eight, with the expulsion of Pluto? But earth is a single data point.
Planets with “intelligent” life: another wild guess.
Planets with communicative “intelligent”: yet another wild guess.
Planets where “intelligent,” communicative life sends can and will signal across space—coincident with our ability to receive it: wild guess again, but bear in mind that we’ve been able to broadcast for only 0.000000001% of the time life of any kind has existed on earth.
The bottom line: When the pandemic is over, starting hugging again. “Intelligent” or not, we humans are probably a rare breed—at least in this corner of the galaxy. Based on Hubble findings, our 100-to-500 billion-star galaxy is only one of an estimated 200 billion galaxies in the observable universe.
(Remember to subscribe to this blog and receive notifications of new posts by email.)
© 2020 by Eric Nilsson
