By John Prytz
SETI stands for the Search for Extra-Terrestrial Intelligence. Kindly note that the word ‘radio’ appears nowhere in that phrase, yet searching for artificial radio transmissions from extraterrestrial civilizations seems to be near synonymous with SETI, as reinforced via the popular movie “Contact” (based on Carl Sagan’s novel). Now there is nothing wrong with radio SETI. The search for radio waves has been well thought out and would appear to offer up the maximum chance for success. But, there are more ways to skin the SETI cat (as it were), and after 49 years of searching primarily via radio, I suggest that some more ways be adopted and explored. Any part of the electromagnetic (EM) spectrum is suitable and up for investigation, such as optical SETI (looking for laser beams) or infrared SETI (searching for Dyson Spheres) or just looking for alien artifacts (as in the novel/movie “2001: A Space Odyssey”). From that, we note that one can approach the study of UFOs and/or ancient astronauts as representing a form of SETI. Whatever investigation tells you that extraterrestrial intelligence (ETI) exists, or once existed, or doesn’t exist at all (and a negative result is as important as a positive one) is SETI.
Why do SETI at all? That is an obvious first question. Fortunately, there are lots of good answers to that question. There’s pure scientific curiosity for starters – exploring just for the sake of exploring. Then there’s the more philosophical approach in that SETI helps to better determine our place in the cosmos. A negative answer is just as important as a positive answer in determining whether humanity is unique, top of the heap, one of the great unwashed cosmic crowd, or the new boy on the block. SETI has a practical side too in determining the existence of potential neighbors which could be sources of benefit and/or threats to us. Obviously, a select few scientists, SETI enthusiasts, have long felt that SETI was, and is, worth doing. Radio SETI is (as of this writing), a quite mature science now 49 years old.
Now if seven is a lucky number, then seven times seven should be even luckier, yet, some 49 years after the first radio SETI experiment (Project Ozma) was conducted by Dr. Frank D. Drake, there’s be no luck in detecting any sign of any other technological extraterrestrial civilization (49 years as I write this – it’s even longer now). What does this suggest to us as a life form with an evolved technological civilization? Where are our ‘kin’ out there among the stars?
Firstly, it suggests that radio SETI isn’t going to be quite as easy as first envisioned. The number-crunching back in those early days suggested that ETI with a suitable detectable technology (radio emissions or rather transmissions) would be pretty common. Even though only a relative few of those haystack stalks have been sifted for that needle, it’s becoming clearer that form of SETI isn’t going to be easy; N (the number of technologically radio communicating ETI in the cosmos) isn’t going to be an extremely large number. So, some constraints on the SETI concept and logic have come home to roost.
In terms of the search to date, it’s clear (to me anyway) that there are no Type III civilizations (able to harness the energy output of an entire galaxy) in any galaxy even remotely ‘close’ (in cosmic terms) to us. If there were any Type 2 civilizations (ability to command the energy output of an entire star) nearly in our own galaxy it should have proved pretty obvious by now. There have been of course many false alarms, but also a few cases that looked like a positive signal was received. Alas, all have been one-offs and have never been picked up again. Without verification, those ‘wow’ signals remain enigmas, but not proof positive of extraterrestrial intelligence (ETI).
Firstly, my explanation as to why we haven’t detected ETI via radio-SETI 49 years on. I consider it unlikely in the extreme that any ETI would deliberately target our parent star and solar system. We’re just too average. There’s no compelling reason to target Sol as opposed to hundreds of thousands of other stars. Even if they did, what are the odds that their targeting us would just happen to coincide with our evolving the requited technology to detect same? What if we were targeted, but thousands, maybe millions of years ago? ETI gave up the ghost and targeted elsewhere!
The alternative is that we could detect ETI electromagnetic (EM) leakage. Alas, if we’re typical, EM leakage (radar, radio, television, etc.) will probably be something fairly short-lived in the history of a technological civilization. Our serious EM leakage is less than 100 years on, yet already the writing is on the wall that our own leakage is rapidly diminishing. Consider that one can get cable TV, radio over the Internet, etc. Earth is rapidly becoming an electromagnetic quiet location. Within another century we’ll probably be leakage free, or as near to it as makes no odds. So, what’s the probably one civilization will detect another civilization’s leakage, if said leakage only exists for a small fraction of that civilization’s existence? Also, relative to deliberate targeting, leaking isn’t very intense and thus ever less detectable at ever increasing interstellar distances. Increasing distances increase the odds that there will be a receptive ETI within the increasing spatial volume, yet by the time the odds are good for finding such an ETI, the intensity of leakage has faded too much to be detected. But still the search goes on.
It is said that the optimist is frequently, in fact usually disappointed while the pessimist frequently or usually isn’t. So is SETI a suitable research venue or course of inquiry for the optimist or the pessimist? I suggest here that to do SETI you need to be the eternal optimist, while realistically, SETI is for pessimists! Traditional SETI searches for photons, traditionally radio, increasingly optical and intra-red (IR), emitted by an ET technology, to date, going on five decades, has resulted in, well, no dice. Maybe there is no ETI, or maybe there’s ETI but little in the way of their manufactured photons.
There are two ways we can uncover, discover, or detect photons from an ETI. Firstly, there’s detection via the leakage of their microwaves emanating from their radio, TV, radar, etc. technologies. Such leakage escapes into space and ultimately finds there way to Earth, landing unto photon detectors at the business end of our telescopes. There are two difficulties with that scenario. Leakage, the tiny leftover residue of what was meant for local consumption, is going to be weak for starters, growing rapidly weaker as it dilutes quick-smart as it spreads throughout the vastness of three dimensional space. That makes it relatively hard t detect and recognize it for what it is. The other reason is that the time frame of a civilization’s leakage could be very short lived, relative to the duration of that civilization, if we are anything to be judged by. Increasingly information is being transmitted by cable (no leakage), not broadcast. So, if you want to detect leakage photons from a civilization that exists for, say one million years, wherein that leakage lasts for only several hundred years, well, the odds are very much against you existing at the very time span when the leakage is happening.
While radio leakage is ‘bright’ relative to the environmental stellar surroundings of an ETI, optical and IR leakage will be dwarfed and drowned out by the ETI’s parent star. The traditional analogy is looking for and detecting the light of a firefly whose is within an inch of a brilliant searchlight. So, little hope in that respect.
The other way of detecting ETI photons is if they deliberately scream their photon lungs out via a targeted radio/optical/IR beacon that says, in one hell of a loud ‘voice’, “Here we are, now where are you?” Is that likely for the vast majority of ETI? Probably not, although there will always be a exceptions to how the majority rules; perhaps so small that it’s of relatively little SETI consequence.
There’s reasons why we (taking ourselves as an average ETI are afraid of the dark and mark on unexplored maps ‘here they be dragons’. It’s fear of the unknown. Any ETI civilization, with emerging photon technology, hasn’t a clue what’s out there and what the potential dangers might be from other ETI’s. Discretion is the better part of valor; it’s better to be an alive coward than a dead hero. Maybe you can’t hide, but that doesn’t mean you need to draw unnecessary attention to and self-advertise yourself. I mean if you’re walking down a dark alleyway and see a gang of hoods in the distance you don’t exactly draw attention to your situation. Maybe they won’t notice you if you act in an inconspicuous manner. When faced with the unknown and potentially unknown adversaries, you err on the side of caution, self-interest, and survival. “Be afraid, be very afraid” is a good strategy, and live to be scared another day.
You can’t assume that the Universe is full of cuddly and friendly ET teddy bears – here they be Klingons in the uncharted maps of deep space is a better, safer assumption. OK, so we ourselves transmitted a beacon, a signal, to M13 many years ago. This aroused a storm of protest at the time. It was an elite, incredibly tiny minority of scientists who took it upon themselves and made a decision on behalf on the entire human race, to signal our existence to the Universe – well M13 anyway. Nobody asked for your okay, did they? Of course the counter argument was that we were already leaking, so no harm done, but then leakage is to a beacon what a candle is to a powerful electrical searchlight! [By the way, I never lost a wink of sleep over the M13 message at any time. Truth be told, it was really more a PR stunt than a serious attempt at shouting to the Universe our existence.]
The ultimate SETI upshot is, what if nearly everyone, every ETI civilization, is running scared and is in passive SETI receiving mode relative to taking the initiative, grasping the SETI bull by the horns, and doing a ‘hello, here I am’ thing? So there’s lots f ETI out there, but SETI won’t discover, or is very unlikely, to discover them.
The search goes on, and the onus, the SETI strategy, is on the searcher. One can’t assume anything about ETI advertising their existence and giving us a helping hand in detecting them.
What SETI is the best SETI? It used to be radio telescopes tuned to the 21 cm frequency of neutral hydrogen (H). Then it became the ‘water hole’, that band of frequencies between neutral hydrogen and the hydroxyl (OH) radical – H + OH = the water molecule, hence the ‘water hole’ (a terrestrial place where many different species gather together for a common purpose). Since then, lots of astrobiology/SETI scientists have proposed lots of other possible radio frequencies, such that today, SETI searches tend to be broad spectrum ones rather than focusing on just one or two frequencies.
So, what SETI is the best SETI? Well, SETI has to be affordable and practicable. Expensive and exotic technologies probably won’t attract many research grants. To make that economic long story somewhat shorter, it got me to thinking that there’s a cheaper SETI option than current radio SETI. I refer to the mega-reams of ordinary astronomical data bits that must reside in various repositories. I don’t know how many bits of information in total exist, but I’d wager its lots and lots – enough to fill up an Australian Federal Parliament House perhaps!
Now over many decades of astronomical observations and data gathering, be it from the surface (optical and radio telescopes), balloons, satellites (in particular declassified data from military satellites), and space probes, ordinary astronomers have looked at same, written their peer-reviewed papers, and moved on to new topics of interest and observations. The interesting bit is that here we have these reams of data (and publications) by astronomers who had no interest at all in extraterrestrials (ET’s), ETI, or SETI, yet who might have, by accident, stumbled across an ETI signal without realizing it – because that wasn’t their agenda.
So, if someone with that agenda, were to comb through that already existing data (note – no need to request telescope time and associated hassles), then maybe, just maybe, there’s an ETI signal in all the pre-existing data-noise.
For example, as noted above, I doubt if ETI would try to draw attention to themselves via targeting solar systems with optical or radio beacons. An easier way would be to inject something unnatural into their parent star. If astronomers were to look at that star’s spectra, and notice something very anomalous, an element that just shouldn’t be there, that would be a potential, and verifiable, bona-fide potential SETI hit.
I’m also pretty skeptical about Dyson Spheres, but have all infra-red objects been closely examined for evidence of same? (I’m not sure how one could distinguish an artificial infra-red source from a natural one, but I’m sure there’s a way, or Dyson wouldn’t have proposed the idea.)
There could be any number of ETI large-scale astro-engineering projects, which could possibly be evidenced by examining existing astronomical data – if one had a view to looking for same from the start.
Another possibility would be detailed examination of the multi-thousands of high resolution lunar and Martian photographs for possible anomalies suggestive of an ETI presence/visitation in the far distant past. I doubt if scientists have had yet the time to closely examine all the photographs that must be on file. The ‘Face on Mars’ proved to be a ‘bust’ (pun intended), but maybe there’s something else awaiting examination and discovery and verification.
Speaking of the moon, there’s lots of observations of, and data relevant to Transient Lunar Phenomena (TLP), which might be suggestive of ETI since one might be hard-pressed to come up with geological solutions.
Anyway, the real point is that there are lots of possibilities of examining existing astronomical data for evidence of ETI.
As suggested immediately above, there needs to be a multi-approach to the issue. One doesn’t want to have all one’s SETI eggs in the radio SETI basket. Here are a few other approach suggestions.
There’s one approach in particular I find compelling. ETI will (at least initially) explore their cosmic environment via interstellar unmanned probes, not unlike our Pioneer 10 and 11, or Voyager 1 & 2 probes, albeit ours were local explorers not designed to explore other solar systems. The advantages of the (initial) unmanned approach is that such probes will be lightweight (no shielding or other life support systems required) and one-way, probably nuclear powered during flight, perhaps solar powered at voyage’s end. The main components would be bits for broadcasting, detection instrumentation, and propulsion. Such probes, designed to survey only ‘seek out new life [in general] and new civilizations [in particular]’ (among other scientific objectives) would be passive. They would scan alien solar systems for biological signatures (like planetary atmospheres in chemical disequilibrium) and zero in on those listening for indications of electromagnetic radiation with intelligent signatures. The probes wouldn’t actively broadcast to such worlds, rather communicate back any findings to their home world’s civilization – again, alert that populace of a potential neighbor which could be a potential (short or long term) threat.
So, assuming alien probes have probed our solar system, yet aren’t going to say “hi” – maybe they are already dead; no technology lasts forever – a SETI approach would be to look for them, a hard task I admit since probes will be small, and our solar system is vast by comparison.
In summary, here are a few fairly low cost SETI strategies. 1) Radio surveys of entire galaxies (billions of stars at a go) looking for an ultra advanced high technology civilization, the sort that would stand out in an entire galaxy. 2) Surveying nearby sun-like stars for electromagnetic leakage (like radar, radio, TV, etc.). It’s unlikely IMHO that we would be deliberately targeted by an optical or radio beacon, so we need to look for EM leakage. Because that would be relatively weak, the stars will have to be close, and should be similar to our sun. 3) Intense examination of highly detailed photographs of the moon and Mars for any signs of artificiality. 4) Examine with a fine tooth comb any existing astronomical data for anomalies suggestive of intelligence. For example, there could be anomalous spectral lines in stars, giving away the presence of atoms that shouldn’t be there but which were dumped into said star by ETI as a ways and means of attracting attention. 5) There should be a scholarly examination of terrestrial mythology, especially religious mythology, for hints of ETI. For example, do all gods in all the worlds religious mythologies live in the sky (like Heaven, or Valhalla) and possess magical (technological) powers? 6) For once, there should be a serious examination of the UFO data to determine once and for all if there is a case for some UFO events exhibiting ETI technology.
I’ll wager one prediction based on past scientific discoveries. The first is hard, but when achieved, it leads to a flood of other similar finds. For example, in astronomy, there are extra-solar planets which were a long time in the detecting; today they are being discovered by the bucket load; likewise with Kuiper Belt objects, or near-Earth-crossing asteroids, or in biology, the discovery of extremeophiles or hydrothermal vent communities. Once you start looking and find one, Pandora’s Box just pours out her contents. I predict the same will be true in SETI. The first find will be long and hard – the next 100 discoveries will be short and easy.
I wish to make it clear that I totally support radio SETI to the hilt. It is bona fide science. Nothing ventured, nothing gained is applicable here. It’s just that radio SETI isn’t the only game in town, and I equally support and encourage any and all other search strategies. The sole exception is that if one wants to look for signs of ETI in other galaxies than our own, then radio SETI is just about the only game in town.
Conclusion: Don’t put all your SETI eggs in the electromagnetic (EM) basket.
Science librarian; retired.