When I heard the learn’d astronomer, 

When the proofs, the figures, were ranged in columns before me, 

When I was shown the charts and diagrams, to add, divide, and measure them, 

When I sitting heard the astronomer where he lectured with much applause in the lecture-room, 

How soon unaccountable I became tired and sick, 

Till rising and gliding out I wander’d off by myself, 

In the mystical moist night-air, and from time to time, 

Look’d up in perfect silence at the stars.

— Walt Whitman

Who among us, just like Walt Whitman, has not stood outside at night, looked up at the sky with its thousands of stars (and a myriad of galaxies if we could only see them with the naked eye), and then wondered if we really were all alone in the vast depths of the universe?

Were we really creatures that were the result of a one-off evolutionary outcome from the chance joining up of molecules comprising hydrogen, oxygen, carbon, nitrogen and a few trace elements, and that, further, nothing like it has ever happened anywhere else in the entire vastness of space? 

And then, almost inevitably, while looking upward, our thoughts would turn to the great puzzle of where all those other sentient creatures are. Why haven’t they contacted (or even visited) us already? And most pointedly, if they are out there, now that they know we have reached a certain level of technological sophistication — capable of both sending a plethora of our electronic messages out into the universe and exterminating our species and all the other life on the planet with nuclear weapons or from the worst effects of the anthropocene era — where the heck are all those others?

Webb’s First Deep Field (NIRCam Image). Thousands of galaxies flood this near-infrared image of galaxy cluster SMACS 0723. High-resolution imaging from NASA’s James Webb Space Telescope combined with a natural effect known as gravitational lensing made this finely detailed image possible. ebb’s highly detailed image may help researchers measure the ages and masses of star clusters within these distant galaxies. This might lead to more accurate models of galaxies that existed at cosmic “spring,” when galaxies were sprouting tiny “buds” of new growth, actively interacting and merging, and had yet to develop into larger spirals. Ultimately, Webb’s upcoming observations will help astronomers better understand how galaxies form and grow in the early universe. Image: NASA, ESA, CSA, STScI

Of course, like so many other really big things, there are several schools of thought about such questions.

One version has it that the aliens have, in fact, already been here; that maybe they are still here among us, but we just can’t see them because of their ingenious cloaking devices or whatever, and they are intent on watching us make galactic fools of ourselves — and they are only occasionally spiriting a couple of humans up to their ships for their biological research or amusement as exotic pets.

Another version is that they have been here before, but because we seem so intent on killing each other, there is some kind of very hi-tech galactic caution sign — or even an actual quarantine — a couple of parsecs away from Earth with a warning posted: “This area is restricted. No access without prior approval from the galactic authorities.”

A third major version is, of course, that we really are alone.

The ancient religious doctrines have held such a view, with the added concept that we have been created in the image of a deity. Perhaps, it has also been speculated, this is because any species that reaches a certain level of technology inevitably destroys itself. Or, alternatively, it is because we, here on Earth, really are unique and there has been no other similarly successful evolution out among the googolplex-squared inventory of stars. 

Still another variant response to this challenge is that on all other exo-planets with the right environment, it is bizarre microbes or really big bugs, or smart fish-like creatures, or even virtually indescribable things that rule, but there have never been any real bug-eyed monsters with magnificent, seriously effective cerebellums — but coupled together with evil intents and very bad attitudes. 

Or perhaps there are truly godlike creatures, with unimaginable powers, for that matter. But the vast distances between stars will obviously make it difficult to arrange a get-acquainted party without that warp drive so beloved of science fiction writers.

A bad idea?

In fact, some serious exo-biologists (and there is now such a scientific field of inquiry) have even suggested it would be one very, very bad idea to try to make contact with other civilisations beyond Earth. The reasoning is that if they have been watching our television shows, reading our emails, and listening to the contents of right-wing talk radio via radio waves, they may very well decide to come here, because — as many SF stories have suggested — they will come to view us either as a tasty bit of easy-to-raise cattle; determine we are vermin that must be exterminated before we infect other planets in the galaxy, or they may decide to terraform our planet to suit their own tastes, but one that requires a very different atmosphere than the one in which we are able to exist. Such a first contact as that would be an existential moment for sure.

Every fan of speculative fiction, or as it is often called, science fiction, has almost certainly read or watched dozens of explorations of just these questions. However, almost all of us have usually moved on to more pedestrian or more pressing earthly issues before reaching conclusions to such questions.

SETI

But some scientists never stopped wondering and thinking about this very big question — as part of a search for extraterrestrial intelligence, or SETI, as it usually is called. 

One of the foremost of these was the late Frank Drake. And throughout his long career, he inspired, influenced and guided many others (including Carl Sagan) in this same quest. 

Drake has now died at the age of 92 (see the detailed New York Times obituary, among many others: Frank Drake, Who Led Search for Life on Other Planets, Dies at 92), after having spent decades creating or inspiring a series of projects that sought evidence of extraterrestrial life and, crucially, the big enchilada — intelligent extraterrestrial life. 

Revolutions in astronomy

This effort has gone hand-in-hand with a virtual revolution in astronomy. Actually, there have been several concurrent revolutions that have all helped move this speculation away from the movies and SF novels and on to serious scientific endeavour.

The first of these was an explosive growth in available computing power to analyse and make sense of a universe of data that floods in. In fact, one of Drake’s ideas was to make use of surplus number-crunching in thousands of individual computers sitting idle while their owners were asleep.  

The second has been a massive growth in the kinds of telescopes — both terrestrially based and those being parked in space — that can collect a much fuller range of radiation from beyond visible light wavelengths, thus providing yet more data for the identification and measurement of exoplanets.

Most recently among such instruments, there is now the massive James Webb Space Telescope that is primarily receiving a massive flood of infrared radiation, rather than just the more usual range of visible light. 

The final revolution has been a more general appreciation of the reality of the existence of exoplanets, and thus the greater possibility of there being planets suitable for life as we could recognise it, and thus the possibility of intelligent life. That moved the whole question from the realm of SF to serious astronomy, just as someone like Frank Drake had hoped it would. 

Pioneering astrophysicist Frank Drake has died, but his equation for alien intelligence will provoke us forever

The Drake equation

For decades, Frank Drake was in the thick of this star gazing. Besides originating or guiding a variety of actual efforts to find the radio wave evidence of intelligent life on one of those exoplanets, he famously originated the Drake equation to help clarify the chances of such a discovery — a virtual close encounter.

This famous probability-based equation (or, perhaps a well-informed, thoughtful, guesstimate) argues the following case: 

Where the number of civilisations in our galaxy with which communication might be possible (ie which are on our current past light cone), N =

R∗ = the average rate of star formation in our Galaxy ; x

fp = the fraction of those stars that have planets ; x

ne = the average number of planets that can potentially support life per star that has planets ; x

fl = the fraction of planets that could support life that actually develop life at some point ; x

fi = the fraction of planets with life that actually go on to develop intelligent life (civilisations) ; x

fc = the fraction of civilisations that develop a technology that releases detectable signs of their existence into space ; x

L = the length of time for which such civilisations release detectable signals into space.

The bottom line to be drawn from this thoughtful guesswork, boiled down to its crux, is that with all those billions of stars out there, there must be a prodigious number of them where intelligent life could be existing now, or has existed in the past. (Of course, past civilisations could have set in motion communication or signals eons before and subsequently had their own version of a nuclear Armageddon. We may never know for sure.)

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A really big problem, of course, is that actually getting to meet up with the ETs may be an insurmountable challenge. After all, the distances are so huge between Earth and the planets of almost every other star that the travel time, even if we (or they) were able to move at near the speed of light, would still be measured in many thousands of years for any physical transport (unless, of course, we  — or they — develop a warp drive and figure out the actual reality and practical utility of wormholes). Otherwise, it could take centuries even to get as far as just an exchange of greetings that might go along the lines of:

“Hello, how are you? Where are you?”

“Hi back at you. We are far away. But who are you, and what do you want? Are you hungry?”

(Hopefully, the real such interaction would not mimic the secret contents of the guidebook for the aliens landing on Earth that is the horrific key to the short story and later a “Twilight Zone” episode — “To Serve Man.”)

Universal translator

But any such communication could only happen if some kind of commonly understood medium might actually be imagined. 

The fictional universal translator or babel fish may not be available for a while yet (and Google Translate may not be much help either). However, the usual argument is that basic mathematics and physics of the universe are a kind of common language — if the two sides could agree on how to make use of them for communication. 

(Image of Orion beyond the Moon by Matryx on Pixabay)

One frequently suggested candidate is making use of the wavelength of the hydrogen atom — the most ubiquitous atom in the universe. Modulate the information carried on that wavelength (using a prodigious amount of energy to send messages encoded like a binary, on-off version of Morse Code perhaps), and then that could be such a channel.

Here again, Drake was an early exponent of trying to figure out some kind of initial, early answer for that crucial question by means of tangible objects. (There should be a bit of humility in all this. In speaking about wonderful socratic dialogue with ET, one should still keep in mind that back here on Earth, we don’t yet have clearly understood channels for communicating with whales and dolphins. Furthermore, there are a number of ancient writing systems that still elude our comprehension.

Accordingly, Drake and his associates worked out the imagery for a special plate affixed to the skin of the Pioneer 10 and 11 space probes. It made use of a system of encoding based on an understanding of the hydrogens atom’s wavelength, translated into the mathematics of base 2.

If one cracked the code, presto, its message would resolve into a visual explanation of where the probe had come from, and who had sent it (including an illustration of a variation on Leonardo da Vinci’s “Vitruvian Man”) and — perhaps crucially — that we earthlings intended no harm to the recipients of the probe — the “we came in peace for all mankind” gambit.

Serious science

All rather Star Trekkie stuff, to be sure, requiring one to cue up that famous theme music right about now – but this was serious science, too, and government money was paying for it. 

In fact, the two probes are still journeying outward from our solar system, and, maybe a few thousand earth years from now, some sort of creature may come across one of them when it bangs into one of their spacecraft. 

As an aside, to try out the feasibility of the code, Drake gave a version of the plates to a group of really bright sparks. But it turned out that none could successfully decipher the meaning of the message. Hopefully, the denizens of an exoplanet circling Epsilon Eridani or Proxima Centauri, or wherever, will have better intuitive and deductive powers than that gaggle of earthly physicists — if they ever engage with those probes.

Throughout his career, too, Frank Drake was a promoter and guiding light for a series of projects designed as serious hunts for the unmistakable electronic signals from some sort of extraterrestrial civilisation. That was certainly more reasonable than it was to expect an encounter with the crew of a flying saucer landing on the lawn at the White House, as in the film, the “The Day the Earth Stood Still”, or when the Vulcans first discovered Zephraim Cochran’s first warp drive in one of the “Star Trek” movies. 

Drake’s initial effort in this area was named Project Ozma, so named for the queen of the fictional land of Oz. Using the growing reach of radio telescopes and computer power to crunch the data, he continued this process through a number of increasingly sophisticated projects over many years. 

Arecibo radio telescope

Among other activities, he became the leader of that massive radio telescope built into an immense natural depression in a valley in Arecibo, Puerto Rico, using it for a SETI hunt as well as much other astronomical research. 

When government money was no longer available for Frank Drake’s search for his own white whale, the private, non-profit SETI Institute, of which he was one of the founders, became home base for such efforts. (See: www.seti.org for a comprehensive review of these programmes and projects.) There has been no positive result yet, but the search is still young and the tools are only getting more sophisticated and powerful.

An encounter with Drake

This writer actually talked with Drake some 60 years ago. I was doing a science fair project in middle school on meteor showers and an effort to visually determine the apparent origin points of meteors in a shower, using a star map, the human eye and a ruler. This project required hours and hours of reclining on a lounge chair in a vacant lot, wrapped in several blankets, a hat, gloves and several scarves. The police patrols through the neighbourhood probably thought I was a harmless lunatic.

On one of the chilly nights, as I was carefully marking my star chart, I looked up and saw several lights moving quickly in the sky. It didn’t appear to be the standard running lights of an airplane, and there was seemingly no sound associated with them in the night air.

I dutifully marked its course on my chart and then, the next day, I found the astronomer’s mailing address, courtesy of a science magazine article on UFOs. I sent Drake a letter with a sketch of the path and a few days later, after school, I received a phone call from him. This was, of course, decades before email. He didn’t scoff at my observations and simply meticulously guided me through them.

It was apparent that he and his team were constantly updating a database of inexplicable observations. His serious, careful reaction to mine was a key element in convincing me that astronomy was my future. That was, until I finally realised that astronomy required physics and calculus, and that was a turning point in career choices. But that is another story.

If and when the SETI Institute actually does find the proverbial needle in a haystack of cosmic noise, perhaps, then, a statue of Frank Drake will be erected, to mark his persistence and prescience. He will surely deserve it. DM