METI matters

Is it unethical to try and contact aliens ? This guy says yes, it's much too dangerous and we should stop immediately. He has some very good points and it's a genuinely entertaining read. Unfortunately, and inevitably, he misses at least one TRULY OUTSTANDINGLY OBVIOUS point, but let's start with the good bits.

Our electromagnetic (EM) emissions leave Earth at the speed of light. EM that left Earth in 1930 has already swept over approximately the nearest 7,000 stars... Further, the Earth grows quieter annually as more information is transmitted via cable, the Internet, and satellites rather than terrestrially over the air. Unless ET’s receivers are both powerful and omnidirectional, they will not detect us. ET’s receivers could be omni-directional, but unable to pick up a signal so weak as the proverbial I Love Lucy. For example, the gigantic Arecibo radio telescope could not detect terrestrial TV transmissions, if broadcast from the distance of our nearest neighboring stars.

Which are very nice informatics to have in mind. 7,000 out of ~400 billion is not so many, and if our signals aren't powerful enough to be received by technologies comparable to our own, then this gives us little constraint on who's listening. Much the same can be said for listening :

The SETI Institute (SI) has only examined less than one star in 50 million in the Milky Way. Even then, this limited set has been studied in real time for only ten minutes each, only across certain frequencies, and only using certain detection algorithms. Jill Tarter, SI’s lead SETI scientist for most of its history, often likens this to having dipped a drinking glass into the ocean. The fact that no fish appear in that first dip of the glass, hardly means that the ocean is lifeless.

From which I think we can generalise an important point :

1. At present we have no meaningful constraint on the number of extraterrestrial civilisations in our own Galaxy with technologies comparable to our own.

Harder to infer is what we can say about civilisations greater than our own. I tend towards the view that the Fermi paradox is not yet resolved, that the Galaxy should have been colonised many times over by now, that the signs of a Galactic Empire would be obvious. There are some arguments against this, of course - that aliens aren't transmitting in ways we understand, that they keep us in a cosmic zoo, etc. The author glosses over this, which I found a bit strange if the goal is to convince the reader that the Galaxy is a dangerous place.

We next come to the point I think is very obvious. Surely the advanced aliens we should worry about would already be able to detect us ?

METI-ists argue that ET can surely monitor Earth already... [but] ET would have to deploy many millions of these gravity telescopes in order to reliably detect Earth’s leakage of the last 100 years. The ineffectiveness of ET’s conventional radio telescopes in detecting our leakage has been analyzed by Billingham & Bedford, who conclude that ET’s radio telescopes would not only have to be truly gargantuan, but pointed at Earth for an extremely long period of time in order to detect our leakage.

Right, but in order to inflict harm, you're going to need gargantuan resources ! So this is my second important point :

2. The resources required to harm or destroy a civilisation at a distance of multiple light years always exceeds the resources needed to merely detect it.

If this is not so, it needs to be robustly demonstrated, otherwise the case against METI collapses. Now he says very fairly :

As advanced as they might be, a carbon-based ET will probably not travel hundreds or thousands of LYs just to eat us. Big Macs cannot be that expensive on its home planet. Nor are they likely to spend 50, 500, 5000, or however many of their generations traveling here just to conduct a bombing run. They cannot hate us that much (or so we hope).

I would accept that aliens just might possibly enjoy sterilising planets just for the hell of it. But this takes resources - enormous resources. The author claims :

Contrary to sci-fi movies, ET would not need a space armada in the style of Independence Day to destroy life on Earth. A single bullet sized projectile filled with the right self-replicating pathogen or nano-grey-goo might do the job.

But this would have to be fired at relativistic velocities in order to guarantee that it would reach us - unless the aliens have mapped every bullet-sized bit of debris between us and them, any probe would otherwise need to make course corrections. And if they've done that, then they certainly already know about us. There's no way to avoid an ET with hostile abilities having gargantuan capabilities that exceed the capacity to detect us. Alternatively, they could have filled the entire Galaxy with missiles programmed to seek us out, so there could be such devices already lurking on our own Solar System :

We currently have no evidence for or against ET probes orbiting the sun because we have never looked for them. There could even now be literally thousands of probes sitting on asteroids transmitting messages to Earth (so many, because probes could have arrived from multiple civilizations; from the same civilization sending regular updates over the eons; or because they are von Neumann replicators). We would not know this simply because no one has ever systematically trained a radio telescope on the ecliptic.

But if they were so close and hostile they would already have detected us and wiped us out !

Let's return to the extrasolar scenario. Sending a blob of deadly goo is speculative in the near-magical vein, but it gets worse :

Alternatively, ET might employ a fairly small kinetic projectile accelerated to a significant fraction of the speed of light. The asteroid that did in the dinosaurs was traveling at about 6 miles a second, or a mere 0.003% of the speed of light--a very lazy crawl. Such projectiles could be launched from ET’s home systems, just as we have launched Pioneer, Voyager and New Horizon into interstellar space from ours.

Egads, just because it has a low mass doesn't mean a relativistic projectile doesn't require stupendous amounts of energy. And while a single replicator doesn't require much initial energy, it would seem to make the construction of alien-detecting equipment an obvious first step - if you could do this for free, why wouldn't you ? It would make no sense not to do so if you wanted to wipe out other civilisations. So I maintain that the burden of proof lies firmly on those who think there's a way to harm other species living many light years way without first being able to detect them.

Korbitz, acknowledging a total lack of evidence uses that very lacuna to argue in favor of METI: “Given this vacuum of knowledge, we do not currently have reason to believe that Active SETI is inherently risky.” With equal cupidity one might walk in the woods, cloaked in complete mycological ignorance, and commence eating whatever mushroom happens to look delicious.

Yeah, but worrying about aliens with capacities bordering on the magical makes no sense - you might as well worry about being eaten by swamp demons. Better stay away from that swamp in case a demon eats you. What demon ? The magical one with the flaming sword. You know, the one that we can't prove doesn't exist. Or we might as well say that we shouldn't even look into space at all in case the aliens can sense what we're doing and don't like it. Really, one can say, "but they might have an unknown capacity to do me harm" in literally any situation at all. Again, justify how they could inflict harm without already having detected us, and then we'll talk.

Finally :

If they would transmit from Arecibo today, as Shostak and Vakoch proposed to the board of the SETI Institute, they must also reserve Arecibo, or its equivalent, for that future date. Of course, they have not. In fact, Arecibo will probably be decommissioned long before then.

That, sir, is simply mean.

Give all of our culture, religion, technology and science away for free and ET might laugh up its sleeve at such fools. Why should they bother to respond? What more would they have to gain, especially since communication might involve significant risk that either the intended recipient or an eavesdropper in our star’s foreground or background might be hostile? 

Ooo-kaaaay.... he wants us to sell things to aliens. Good grief.

Reviewing METI: A Critical Analysis of the Arguments

There is an ongoing debate pertaining to the question of whether Earth should initiate intentional and powerful radio transmissions to putative extra-terrestrial (ET) civilizations in the hope of attracting ET's attention. This practice is known as METI (Messaging to ET Intelligence) or Active SETI.