by  Kanaka Menehune 

Disclaimer: I’m about to throw a lot of high-concept stuff in your direction. And some of it involves, like, math. I am not a mathematician. It is not only possible but probable that I’ve made a mess of any calculations involved in what is below. It also involves a lot of science-stuff. I did some research to make sure that I had it as right as I could get it, but I have inevitably made some mistakes. Don’t take anything I say below as gospel. Feel free to point out my mistakes, and please bear with my wilder flights of fancy. :)

Thought experiment.

I take you and a random stranger aside on separate occasions.

I hand you a nice telescope. I say, “Every night for one year, I want you to take this outside any time you like, after dark, but before dawn. Point it in any direction you like for exactly ten seconds and watch carefully. If you see a small, bright light blinking once every second, call me.”

I hand the stranger an extremely bright LED light. To them, I say, “Every night for one month, I want you to take this light outside at any time you like, after dark, but before dawn. Go to the same place every night. When you get in place, hold it above your head and blink the light on and off ten times, spaced one second apart.”

To both of you (but separately), I say, “You can start doing this any night you want. Try not to miss a night, but if you have to, make it up at the end. And don’t talk to each other.”

What do you think are the chances that I will get a phone call from you because you saw the stranger’s light blinking?

I first wrote a version of this on my old website many years ago. This version is, I sincerely hope, clearer and better explained. It was to point out the difficulty of looking for signs of extraterrestrial intelligence using our then-current method of pointing a satellite dish at a star and “listening” for a short while, then moving on to another. Basically at random. If there truly were any ETs out there making an interstellar — or intergalactic — call, what are the chances they’re talking while we’re listening? What are the chances that we happen to be at the same level of technology (more or less) during the same span of time? What are the chances that both our species are long-lived enough (as a species) to have a meaningful dialogue? What are the chances that both our species’ version of ‘government’ or ‘research grants’ would fund something of that sort?

At the time I wrote the original, we had discovered maybe two or three planets outside our own system. And those were all hot Jupiters, massive worlds orbiting so close to their stars that they were too hot to support any kind of life that we would recognize as life. Now we know of thousands of exoplanets, and we believe (with evidence) that planets are common, not rare. We even have telescopes in orbit — Kepler Space Telescope and TESS — designed specifically to look for new planets. The methods we used to find those very planets suggest ways to improve our search for ET if he’s out there. We can detect planets around other stars best if the extra-solar system is ‘edge-on’ to us — in other words, we spot planets by the dimming of their sun’s light when the planets’ orbits put them between Earth and their star, dimming the light enough that our computers can detect it.

It means that we can refine our search to those stars like our sun around which we have detected at least one planet. We can direct our search at stars for which our system is edge-on.

Our signals are designed for our equipment, of course. But EM (electromagnetic) radiation is ubiquitous across the entire universe. From radio to gamma, it’s all just light. We mostly use radio and microwaves in our communication (radiation starts getting dangerous at x-rays and up). Depending on the type of signal and the intended receiver, the information (audio, video, etc.) is coded by modulating the waves. It’s probable that these are obvious enough that an alien species would figure that out. I mean, we did pretty quickly after realizing EM existed and how it works.

EM radiation spreads out from its source in a spherical wave. The strength of the signal gets weaker in proportion to the square of the distance from the source. At interstellar distances, the signal is so weak, we might not even recognize it as a signal; it might get lost in the random noise between them and us.

There may be ways to overcome the loss of strength. Consider a civilization advanced enough that they have figured out how to encode their information using some physical property of the photons themselves. For instance, the “spin.” Although the number of photons arriving at the destination would be few, the “signal” would still be “strong” unless something interfered with the photons’ spins between the source and the destination. Would we even recognize this as a signal at our level of technology?

We have a narrow band of the EM scale we use to encode radio and television. Radio is electromagnetic waves (light) that we use to encode sound. The light is then re-translated into sounds (vibrations in a medium, and that medium is 78% nitrogen, 21% oxygen, and 1% trace elements (at atmospheric pressures comfortable for humans)) detectable by human ears, roughly 20 Hz to 20,000 Hz (20 kHz). Our evolution dictated the range in which we can hear. Other animals here on earth hear in vastly different ranges, some very low sounds (elephants, for example (14-16 Hz)) and some teeth-gratingly high ones (bats, for instance (up to 115 kHz)). How different might an extra-solar species senses be? Would they even know to interpret our signals as sound? Would their atmosphere even conduct sound waves in a similar way to ours?

A TV broadcast is, at a simple approximation, one of those audio signals paired with a synchronized video signal broken into rows and columns (arbitrary values, which are different even in different regions on Earth) designed to be decoded into brightness values (on arbitrary scales) for the colors red, green, and blue. Red, green, and blue are specific frequencies of light in a very narrow band that humans evolved to perceive with specialized cells in our eyes, based on our specific environment and evolutionary pressures. Other animals here on earth see colors very differently because of different evolutionary pressures. Some (like cats) see a drab (to us) subset. Some (like mantis shrimp) see a profusion of colors we wouldn’t even have names for. Others (insects, birds, etc.) can see in frequencies we know are there, but can only see by false-color approximations (rendering infrared as varying shades of red, orange, yellow, blue, and violet based on temperatures (that are comfortable and meaningful to our particular species, using arbitrary scales); ultraviolet in shades of green, indigo, or violet).

Some species here on earth communicate via the medium of water instead of air (whales, dolphins), in which sound propagates differently. Others communicate with each other via smell and/or body posture. Others “taste” their surroundings (snakes, lizards). Still others use senses we don’t have an analog for, such as platypuses, which detect electrical signals with their bills. Others can sense the variable strength of the magnetic field of the planet. No one is even quite sure how birds and butterflies and fish find their way while migrating. We have hypotheses, of course . . .

If we received a signal from another civilization that was encoded for body posture and smell instead of light and sound, how would we interpret that? Could we ever decipher it? This is why the signals we have sent out deliberately are encoded in a “universal” language of math. The first one thousand prime numbers, for example. Math is math is math, pretty much anywhere you go in the universe, and as long as they could interpret binary, we would at least be able to say, “Yo! We’re here and we know the first 1000 prime numbers! We’re intelligent!”

We can’t understand the communications of any of those animals here on earth beyond a rudimentary level, and we share ~3.8 billion years of evolution with them. You are more closely related to an Ebola virus than you would be to any species that evolved on a planet other than Earth. We are all related more closely than we would be with any extra-terrestrial or extra-solar — or extra-galactic — life. Sure, we’ve modified some of our companion species to be able to better understand us, and we’ve become attuned to them, but do you really know what your dog is thinking? A cat? A raccoon? A cow? A snake? What about a whale, dolphin, mole, bat, or eagle, who exist in a three-dimensional world we have no real concept of? Or an octopus, squid, or cuttlefish, with no skeletal structure and the ability to change shape, texture, and color at will?

And if we could communicate with these animals, how would they describe things to us that are natural to them, but for which we have no basis for understanding? Sonar, pheromones, 3-dimensional movement, chromatophores, flying, swimming, air bladders, electrical sensitivity, magnetic sensitivity, etc.

Given all of the above . . . what are the chances that an alien intelligence, evolving on a different world with different evolutionary pressures, would have any concept on which to approach understanding us, or we them? Or, as put succinctly by Deanna Troi on the episode of Star Trek: The Next Generation entitled “The Ensigns of Command”:

And Troi forgot “refreshing,” “invigorating,” “aromatic,” “ceramic” (if the cup weren’t glass), “caffeinated,” “tannin-containing,” “full”/”half-full”/”half-empty,” “to your health,” “relaxing,” “sleep-inducing,” and a host of other concepts that one might mean when one brandishes a cup of tea in the way she did. Some of which we might not even be able to conceive of. Imagine an intelligent dog holding up chocolate and meaning “agonizing death.”

Now, let’s talk about time. Time is a huge factor, here. It took life roughly 4 billion years on Earth to go from raw amino acids to Homo sapiens sapiens, capable of contemplating ET. Many stars with planets will have gone off the main sequence during that time. Others are still forming as you read this. Perhaps a billion years ago, a civilization was looking for life elsewhere, but we weren’t yet able to hear it, being mostly ocean-dwelling, tiny eukaryotes at the time. A billion years from now, after the Earth’s surface is likely uninhabitable, perhaps some far civilization will spot our signals, but there will be no one home to receive their reply, much less engage in a conversation.

Now, suppose we find someone. Assuming they are farther than about 25 light-years from us, having a “conversation” with them would be unlikely in a single human lifetime, as we would have to detect and decode their signal, then compose a response, and it would take the same amount of time for our reply to make it back to them as it took for theirs to make it to us. We’re talking about a simple two-line conversation

taking at least 50 years. Quite a commitment of time and resources. Speaking of that . . . what are the chances that any civilization would want to spend the time and resources to even look for us? We’ve been listening for several decades, and our own governments here begrudge every cent spent on the endeavor. And rightly so. There are many better things to spend time and resources on than looking for ET.

And all of that doesn’t take xenophobia into account. The late Dr. Stephen Hawking famously pointed out that any civilization that we were to discover would more than likely be ahead of us, technologically. Would it even be smart to announce our presence, given the history humans have amongst ourselves when an advanced civilization encounters a more primitive one? So far, it has never yielded a positive — or even neutral — result for the less-advanced civilization. What makes us think a space-faring alien species would be benevolent? What makes them think we would be? Realistically, we’d be better off hiding all evidence of our existence and hoping that no one detects our radio signals and follows them back to the source.

Why does all this come up? I thought you’d never ask! :)

A while back, it was announced that SETI had gotten a boost in the form of generous support from a private investor. SETI has been around for a long time and has been . . . well, let’s just admit it: they’ve been kind of a joke. No one really expects to find anything, and I’ve outlined above my understanding of how unlikely it is that we will ever find a message decipherable by us. So SETI has been underfunded for a long time. Given very little time on telescopes, relegated to the short bus even amongst the other science nerds.

It’s had some amazing support over the years, mind you. Stephen Hawking, Frank Drake, Carl Sagan, others. Drake’s famous equation

gives us the ability to very roughly calculate an estimate of how many extra-solar civilizations we might reasonably expect to exist in our own galaxy. When he first developed the equation, we didn’t know hard values for, really, any of the factors. We know “N” is “at least 1” (us). Now, we’re able to fill in a lot of those factors with real numbers, or at least much narrower ranges.

All the Drake Equation gives us is an estimate of the number of civilizations (of our level or greater) that we might expect to “find” (in some way) in our galaxy. What it does not cover is all that stuff I mentioned above. If we’re not listening at the right frequency or in the right direction, or if we can’t comprehend the message as a message, then what hope do we have of ever learning the answer to that question I put in the title? Is anyone out there?

Our civilization is leaking signals like a . . . leaky thing . . . that leaks. Come up with your own simile. We have, however, sent out two deliberate physical messages and ten deliberate electromagnetic ones I can find a record of. The physical messages were in the form of gold records attached to the outsides of Voyager 1 and Voyager 2. You can read about the ten EM signals here. The total broadcast time of all ten messages is certainly less than thirty minutes, and spread out over almost forty years. They were also aimed at specific spots in the sky, so would be undetectable for most of the universe. Remember my thought experiment way up at the top of this post, with the telescope and the LED light?

One of those signals was beamed at Gliese 581 in 2008. Our signal will arrive in 2029. Assuming there’s anyone there to receive it, and they somehow decipher it, perhaps they will answer, and by 2050 we’ll have a positive answer to that perennial question.

In spite of the astronomical odds against it, I certainly hope it to be the case, even given the xenophobia factor. Unfortunately, unless medical technology (or the ability to upload our consciences to computers) improves before then, that’ll be all I could realistically be around for. By the time the aliens could receive our reply and reply back, it would be 2092, and I’d have to find a way to live to be 127 years old.

On the bright side, I might be done with my novel by then. :) (HaHa! I brought this sucker back around to writing after all!)

Why did I write this? Full disclosure.

1. I first started writing this rewrite of this post in 2015. I wrote the original sometime between 1998 and 2002.
2. But it’s not the usual kind of thing I publish on this blog because this blog is about writing.
3. This article is only very obliquely about writing. But it’s also among one of my favorite things I ever wrote.
4. So . . . here we are. :)

But to bring it actually around to writing, I love me some science-fiction, even though I typically write more fantasy and . . . I’ll call it ‘horror’ because ‘dark fantasy’ and ‘dark fiction’ sound . . . weak. Generally , it’s very mild horror. One of the things that has always rather bothered me about science fiction is that it makes the assumption that the galaxy — and by extension the entire universe — is teeming with life, including FTL-capable, intelligent species who, for some reason, have an interest in contacting us. Sometimes to conquer/consume. Sometimes to uplift. Sometimes as equals.

As soon as I was old enough to understand the vastness of the universe and the realities of space travel, I realized that most of what I was reading was more science fantasy rather than science fact. Even though shows / films like Babylon 5, Star Wars, and Star Trek are among my favorite things ever, I still realize that it’s very unrealistic. And one day, I got the idea of explaining why.

Do I think we will one day discover life elsewhere than Earth? Maybe?

Do I think there is intelligent life in the universe? Maaaaaybe?

Do I think we will ever talk to it if it is? No.

Do I think any of it has ever been here? No.

Doesn’t stop me from wanting to tell the stories where those things do happen. But I try to keep all of the above in mind when I do. :)

1. I think at the time we were using the dish at Arecibo in Puerto Rico, which is only useful over a span of about thirty degrees of the sky (it is limited because it’s built into a sinkhole and is spherical instead of parabolic), so that narrows our range even further. And, thanks to Hurricane Maria in September, 2017, that dish is damaged, and its future is uncertain.
2. It’s called “the transit method.” There are other methods, of course. One of which is to look for the “wobble” in the star as its planets orbit and their gravity pulls it slightly. We can detect the incredibly subtle difference in its redshift and determine the number and sizes of planets that would cause the star to wobble in that way. Science! :)
3. We could further refine it once we discover more planets that are located within the “Goldilocks Zone” (not too hot, not too cold, but juuuuuust right) of the parent star. Those are the ones most likely to have liquid water, and therefore life that would be most likely “similar” to something we could recognize as life. Life could probably evolve using some other solvent than water, but would we even recognize it as life? The Goldilocks Zone will be different for different types of stars, and there could be more than one planet in the Goldilocks Zone of a given star (Venus, Earth, and Mars, for instance). It is also sometimes referred to as the “habitable zone,” “comfort zone,” and “circumstellar habitable zone.” And of course, it goes without saying (so I’ll say it anyway) that ‘habitable’ means ‘for humans.’
4. In other words, stars located within a few degrees of the solar system’s ecliptic plane, the relatively flat plane in which all of the planets orbit the sun. Ours is remarkably flat, except for Pluto and some of the other dwarf planets.
5. The signal strength at the source is some value “A,” and as it propagates outward from that source, the “A” is spread evenly over the surface of the sphere centered on the source. The formula to calculate the surface area of a sphere is 4Πr² (4 times Π times the radius squared). So at 10 miles, the sphere has roughly 100 times the surface area it does at 1 mile, so the signal is harder to detect. At 20 miles, it’s 400 times the surface area. Etc. This is why radio stations on Earth’s surface have to be so strong in order to serve a wide listening area, and the farther out you get from the station, the worse the signal is. Voyager 1 is less than 20 light-hours from Earth, and its signal is tiny, but still detectable. But we also know where to look and what frequency it uses. It still takes very large radio antennae to pick up its weak signal.
6. By “understand” I mean natively. We can interpret the different barks and meows and neighs and bleats, but we know some of those animals only use those sounds around humans. Fully interpreting what two cats are “saying” to each other is beyond our abilities. We literally have no basis for understanding.
7. And of course, by “all,” I must include plants, fungi, bacteria, viruses, archaeans, etc. Humans are more related to fungi and ebola viruses than we could ever be to any extraterrestrial life, unless you want to get into Panspermia, which is a whole other discussion. :)
8. It is estimated that the Earth’s surface will become uninhabitable in about 500 million years because of a slow, but steady, increase in the sun’s heat output. The surface will be dry and unable to support life. Whatever species might be around at that point will likely have to leave Earth in order to remain viable. Or burrow into the planet itself. Which will be fine until about 5 billion years from now, when our sun will expand into a red giant and consume Mercury and Venus and possibly Earth. Even if it doesn’t consume Earth, the surface of our planet will be so close to the sun, it will make Mercury look polar by comparison. I doubt if even cockroaches and houseflies could survive that. At that point, perhaps Mars will experience a rebirth, if we (or whomever) can find some way of enabling it to retain an atmosphere and gain a magnetic field. Or maybe Ganymede, Europa, or one of the other outer moons.
9. Even if we were to discover an intelligent species around the closest star — Proxima Centauri — each line of the conversation would separated by a bit over four years. “Hi!” <4 years> “Hey!” <4 years> “How’s it going?” <4 years> . . .
10. The value of the equation lies not with the value but the contemplation of it.
    • N is the number of civilizations in our galaxy with which radio-communication might be possible (i.e. which are on our current past light cone)
    • R_* is the average rate of star formation in our galaxy
    • f_p is the fraction of those stars that have planets (we now know this number to be much higher than we once believed)
    • n_e is the average number of planets that can potentially support life per star that has planets (this is the number of planets in the Goldilocks zone . . . for humans, because we’re kind of biased)
    • f_ℓ is the fraction of planets that could support life that actually develop life at some point
    • f_i is the fraction of planets with life that actually go on to develop intelligent life (civilizations)
    • f_c is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
    • L is the length of time for which such civilizations release detectable signals into space

    The above information came from the Wikipedia entry on The Drake Equation

11. Come on. You didn’t expect me to ignore the low-hanging pun entirely, did you?