Following the Drake Equation: Five Stories About Searching for Intelligent Life in the Universe

Noted astronomer Frank Drake passed away earlier this month. Among his many, many accomplishments was a venerable equation with which many SF fans are familiar:

N = R*ƒpneƒ1ƒiƒcL

N is the number of civilizations in our galaxy with which communication might be possible. Depending on the values one plugs into the defining factors, N might be anywhere from very large to very small. Very conveniently for science fiction authors, every possible value of N from very small to very high is filled with story potential. Here are five stories reflecting some of those possible solutions…


(A) The lowest possible value of N at the moment is 1. Our civilization currently possesses several means by which it could make itself known to the galaxy at large, ranging from radio signals to nude selfies with directions to our home, addressed “to whom it may concern.” No answers. Yet. It might well be that we are not alone at the moment, just the very first technological civilization to appear.

Emily Skrutskie’s 2018 Hullmetal Girls features a Milky Way in which not only is intelligent life vanishingly rare, so are habitable worlds. Unfortunately, humans did not fully grasp that no Earth 2 was at hand until Earth 1 had been thoroughly trashed. In the centuries since the fleet fled the Solar System, scouts have found no worlds suitable for human settlement: even the so-called Alpha worlds, the most habitable available, are anoxic death traps.

Maintaining the fleet in the face of meagre resources demands regimentation, or so those commanding the fleet believe. The elite cyborg Scela are a key part of maintaining order. Life as a cyborg demands sacrifice, but there are many means available to convince suitable teen candidates to embrace conversion.


(B) N could higher than 1 but still low. Communication may be possible, but the time lags imposed by light speed suggest that whole civilizations could rise and fall in the interval between signaling the nearest neighbor and receiving a reply. Communication with Extraterrestrial Intelligences (CETI) might consist only of assurances that ETIs do (or at least did at the time of broadcast) exist, rather than any sort of meaningful communication.

David McDaniel’s 1974 novelette Prognosis: Terminal explores this in passing. Its protagonist, a struggling artist, searches for a viable niche. Alas, technological progress and social change have eliminated many traditional artistic roles. In many stories, the solution might be to turn to the stars. However, a signal from a long-dead alien civilization reveals that the far more advanced species failed to develop interstellar flight despite its star’s impending nova. The implication is that if solutions for the human condition are to be found, they will have to be found on Earth.


(C) There is the possibility that N could be high enough that occasional conversations are possible but rare. Even if the average distribution is too widespread for routine conversation, some pairs of civilizations will be closer than the average, while some civilizations may possess time-binding abilities that facilitate two-way communication carried out over surprisingly lengthy intervals.

As far as the humans of Der-Shing Helmer’s Mare Internum (2019) know, Mars is a dead world. Appearances can be deceiving. Mars was not merely the abode of life well before Earth but home to an advanced civilization as well—human astronauts owe their existence to careless Martians spreading life to young Earth. Indeed, life still exists within a last refuge deep beneath Mars’ surface. Thanks to some very poor life choices, Doctors Mike Fisher and Rebekah “Bex” Egunsola will experience the wonders of lost Mars in person.


(D) N could be high enough that interaction between unrelated civilizations is commonplace, if not necessarily routine. This is something of a sweet spot for science fiction authors, so examples abound. This value of N does raise Fermi Paradox concerns (if aliens are so common and can reach Earth, where are they?) but these are easily dealt with in various ways, not least by simply ignoring them.

The intrepid explorers of Stanley G. Weinbaum’s “Martian Odyssey” (1934) and the sequel “Valley of Dreams” (1934) find a Mars rich with a bewildering variety of alien life. If the greater facility with which birdlike Martian called Tweel bridges the communications gap is a guide, some of that life is smarter than humans. In fact, the humans belatedly discover that the similarity between Tweel’s people and the Egyptian god Thoth is no coincidence; Martians (or at least Tweel’s sort of Martian) visited Earth in antiquity.


(E) Finally, N could be very large. The Milky Way could be crammed with intelligent life, waiting for us to overcome whatever comprehensive blind spot is preventing us from noticing them, and for rich, plot-friendly interaction to ensue. Indeed, one could envision humans equipped with star-spanning super-science engaged in a mind-boggling enterprise, some manner of multiyear mission to go where no one has gone before, not counting the myriad aliens they encounter each week, who presumably were there all along. Not entirely sure what one could call a story about trekking from star to star but I am sure some appropriate title will come to mind. Galactic Wagon Train, perhaps.

In Mary Gentle’s 1983 Golden Witchbreed, Earth has, by virtue of a very large value of N and a faster-than-light drive capable of spanning the Milky Way in three months, found itself with an embarrassment of CETI riches. There are millions of civilizations with which Earth could open relations. The challenge appears to be finding a sufficient supply of functionaries to conduct diplomatic relations.

As Dominion diplomat Lynne de Lisle Christie discovers, the real challenge is ensuring that Earth actually understands the alien civilization before dispatching its diplomats, rather than, as in the case of Orthe (the world to which Christie is dispatched) jumping to a plausible but wildly incorrect conclusion. Overcoming cognitive blind spots can be a rich source of personal growth … but only if you survive the experience.



Of course, solutions for the Drake Equation open the door to many narrative possibilities. The five works noted above are only convenient extremes chosen for demonstration purposes. No doubt there are intriguing cases I’ve overlooked, cases readers may wish to discuss. Comments are, as ever, below.

In the words of fanfiction author Musty181, prolific book reviewer and perennial Darwin Award nominee James Davis Nicoll “looks like a default mii with glasses.” His work has appeared in Publishers Weekly and Romantic Times as well as on his own websites, James Nicoll Reviews (where he is assisted by editor Karen Lofstrom and web person Adrienne L. Travis) and the 2021 and 2022 Aurora Award finalist Young People Read Old SFF (where he is assisted by web person Adrienne L. Travis). He is a four-time finalist for the Best Fan Writer Hugo Award, and is surprisingly flammable.



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