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Another less-political topic...

The Search for Extraterrestrial Intelligence has taken a strange veer, of late.  I am cross posting here an informative little rant about the kind of topic that calls for a far more intelligent and far-seeing leadership class -- if we are to deal with a bewildering array of 21st Century quandaries.

Take this as just one example of many... SHOULD HUMANITY ANNOUNCE ITS PRESENCE TO THE COSMOS?

For you neos in this topic, you might want to start elsewhere then come back here. My own expose on this topic (ignore the lurid
illustrations), can be found at:

One person who has expressed views on this is
Britain's own prominent astronomer David Whitehouse:


PS...Still want some red-meat politics? Catch your latest edition of Armageddon Buffet!


Seth Shostak of the SETI Institute recently posted a short essay, once again laying down what should be called the "Standard SETI position" on the likelihood of interstellar travel... and hence any conceivable physical danger that might arise from first contact with Extra-Terrestrial Intelligent Civilizations (ETICs).  I invite you all to have a look, hear him out, then come back here.

Essentially, Shostak seeks to dismiss the notion that interstellar contact can occur in any way that might prove dangerous to either side of such an encounter.  This need has grown more pressing, as some members of the SETI community, in Russia and Argentina and Canada, for example, have sought to expand the process, from its traditional mode of passive listening or "searching" for ETI to a far more assertive program of actively transmitting Yoohoo Calls into the cosmos, multiplying Earth’s radio detectability signature by many orders of magnitude in "METI" or "Message to ETI".  Also called "Active SETI."  

Those who have been pushing this new approach (once dismissed as unwise, even by SETI pioneers Frank Drake and Carl Sagan) have been doing so without ever consulting the wider scientific community, or even their own governments, seeking to create a fait accompli that might suddenly and irrevocably alter human destiny, based upon a series of unproved assumptions.

What assumptions?  Elsewhere, one finds a pervasive and almost religious belief that advanced alien civilizations must automatically and by-definition be peaceful/altruistic. Even though true altruism, in nature, appears to be about as rare as hens’ teeth. (Under Stalinist Lysenkoism, this notion of universal altruism was also tied to an expectation that all advanced life forms would be socialist! A dogmatic element that no longer seems to be part of the standard catechism.)

But Shostak and the Silicon Valley based SETI Institute -- managers of the new Paul Allen radio telescope listening array -- do not appeal to this fundamental underpinning of METI.  In this essay, he instead begs the other one.  The article of faith that interstellar travel is virtually impossible.  And, therefore, there is virtually no chance at all, of deleterious consequences from drawing attention to ourselves

(For the sake of argument, we’ll put aside the large variety of conceivable danger modes -- however far-fetched -- that might arise from purely remote contact, involving no physical interaction at all.  Even if we accepted the no travel premise, there are things to worry about.  But another time.  For broader discussion see:

For now, let us stay focused on Shostak’s essay contending that interstellar physical contact between cultures has to be negligible. He goes farther, by using polemical tricks to plant a further assumption -- that any conceivable physical harm from contact must come from a cliched strawman -- invasion and conquest by a cohesive and aggressive galactic empire.

Let’s take these one at a time.

1. Interstellar Travel - and hence physical contact - can’t happen.

There is a vast literature on this.  The Journal of the British Interplanetary Society has been the principal locale for much of it, across the last thirty years.  If you live near a university library that has it... or if they've digitized... the topic is fascinating!  And, without a doubt, the prospect is a daunting challenge, at best. Essentially, there are three demons blocking us from the stars, and Seth only mentions one of them.  

1a) The vast distances involved.  In some ways, this one is actually the simplest to overcome.  I’ll get back to it.

The other two are:

1b) The Rocket Equation - which shows that you must carry fuel to accelerate the mass of more fuel, just to carry enough fuel to accelerate your cargo, an especially burdensome fact when you figure you need to carry fuel to decelerate, as well.  It’s non-linear and really harsh.  But --

I once saw the late Barney Oliver (a fierce partisan of the Standard SETI Model) try to use the Rocket Equation to "prove" that interstellar flight - even with perfect antimatter engines - would be prohibitively costly, effectively bankrupting even a wealthy home civilization that tried to send such an expedition.  He did this at a conference in Brighton, England in 1987. Oliver started by assuming that the vehicle must carry all the fuel needed to accelerate away from home, then decelerate to its destination... then to accelerate and decelerate home again.  

Robert Forward, in the audience, stood up, incensed at this example of put-up, tendentious reasoning, pointing out the obvious.  That the fuel for the return trip would be made at the destination site and not have to be carried there.  And, since all that return trip fuel didn’t have to be transported on the FIRST leg, that leg would need a couple of orders of magnitude less fuel to start with.  With just a little common sense, the rocket equation then appears much friendlier.

As it does if you ponder a myriad alternatives like "star-wisp" self-replicators that could mass very little, require little fuel, yet make copies of themselves -- or anything else -- upon reaching their destination.  Such things could easily have pervaded the galaxy, by now.  At least with tiny observers.

The important point here is not only that a wealthy, solar-system-wide civilization could easily afford such expeditions, but an even more important lesson -- that intellectual tendentiousness can make liars of any of us.  Because of inherent human self-deception, reciprocal criticism is key!  And you’ll only get that in an eclectic and open discussion, not a closed-access circle jerk among like-minded True Believers.

c) The relativistic mass effect -- where the faster you go - in effect - the more you weigh and the harder it is to accelerate faster-still. This last problem only becomes important if you get past 50% of c.  Above 0.9 c it really hurts.  (Alas, that is the realm where you start to benefit from time dilation.)  The crux?  We are behooved to try and see if travel at below half of light speed can do the job.

Those are the three classic  "demons of relativistic starflight."  Though, striving for honesty, I’d have to add a fourth.

d) Radiation shielding.  It is possible that travelling at high speeds through interstellar space is  really tough on you and your ship, if you hit anything at all, along the way, even cosmic gas.  You may need a bulky arrangement of mass in front of you, to absorb the punishment or turn particles into harmless scatter.  That will be a burden, all right... though our back-of-the-envelope calculations don’t seem impossible.

Note, all of this assumes we don’t get hyperdrive or other sci fi marvels.  For reasons seen below, I have to doubt such is possible, since it would worsen, not solve, the Fermi Paradox. (And this from the sci fi author who included DOZENS of such drives in the Uplift Universe!  Hey.  What I find plausible is one thing.  Imagination and fun are another matter. ;-)

Working through it all, here are some basic responses:

  1. The distances involved are (strangely) the part that worries me the least!  They are only daunting if you figure you have to stay awake -- or alive -- in transit.  Or if you ever want to come home again.  Assuming you can go frozen, or as downloadable code stored by a loyal contstructor probe, or if you go AS a self-replicating probe, or any of a dozen variations, and you aren't in a hurry, then distance is not the worst part... long as you can feed the rocket equation enough to coast at 10% to 50% of c.  

Yes!  Those possible methods of ignoring time and distance are in no way yet proved.  But the sheer number of them suggest that travel should not be dismissed.  (Note, even if humans cannot hibernate or code-replicate, it seems incredible to say that some other species out there wouldn’t be able to.)

  1. The rocket equation is a bitch.  But if you only accelerate and then decelerate once, an antimatter-fueled vessel should be able to leave the solar system, coast at quarter of c, and arrive at another star without bankrupting the home economy.  Wish I had the papers at hand for you.  Look up Robert Forward.  Or the first half of Barney Oliver's paper, not the egregious second half.  (Alas, both have passed away.)

Indeed, though, light sails are the thing!  Especially if the home system can be counted on to beam laser or microwave impulses at you for a long time.  Then you totally evade the cruel Rocket Equation. (Jim and Greg Benford are actually experts on this.)  Yes, without this push, the time scales are slow.  But either way, you can get there.  And those that do it, and make copies, and do it again, will inherit the galaxy.  (Note, by that time they may have lost all interest in planets!  So it may even have happened.  Except we haven't seen the lasers.  Is this getting complicated enough?)

Note that long ago, at a conference I attended in Los Alamos, Jones and Finney calculated that a 10% c ship speed, combined with colonization and needing three generations to send more ships, would still let an assertively expanding race fill the galaxy in just 60 million years.  If it were done by Von Neumann probes, who can set right to work making more probes out of asteroidal material, then the figure is three million years.  Just three million, with a ship speed of 0.1 c.

(See "Lungfish" at:

No, this is not a classic "empire".  No coordinated fleets bearing down on this or that enemy world!  (The absurd strawman erected by Seth Shostak, in order to "prove" his point.)  

Imagine a diffusion that’s much more like rabbits, spreading through Australia.  Ask the farmers down there if they are enjoying that First Contact.  Ask the wallabies.


Frankly, I find all four impediments to interstellar travel to be daunting, with a possibility that one or all of them might -- despite current calculations -- finally turn out to be prohibitive.  

But so far, there is nothing to convincingly force us to pre-conclude they are prohibitive.  Moreover, to do so, without exposing the subject to eclectic enquiry, is simply the height of dishonesty.

No, the thing that makes me start to doubt Interstellar Travel is not derived from any of Seth's arguments, but rather the current condition of the solar system, with our asteroids apparently never touched, and the Earth, with only one episode of sudden life change etched into the rocks.  (The eukariotic boom), across the vast two billion year epoch when our planet was "prime real estate."  

The Earth has been a photographic plate, a SETI instrument.  And it seems to have detected nothing.  Nor have the asteroids been extensively exploited by some voracious wave of self-replication or industry.  That certainly puts a real burden on the travel-is-possible guys.  Oh, it can be overcome in any number of ways.  But it is a worse burden than any of the nonsense Seth Shostak keeps raising.  (He is welcome to switch to this track, instead.  It is far more logical.)


Do I think that METI will bring down some horrid devastation upon us?  Not really.  At least I think the odds are low.  

But I do think it is time for us to start applying good habits to low-probability events that might have devastating outcomes. There are a great many of these, apparently, in the pipeline.  Smart guys like Bill Joy and Michael Crichton and Jared Diamond are already out there, calling for renunciation and paternalistic control, in order to evade these catastrophes.  

In fact, I share the renunciators’ worries... while disliking their proposed methodology.  Given that paternalism has seldom worked, or delivered wisdom, in the human past.  Like most of my fellow catastrophe specialists, at the Lifeboat Foundation, I prefer enlightenment processes of discovery, debate, reciprocal criticism and deliberation/negotiation.  (The one process that Michael Crichton never portrays as even possible, let alone happening, in any of his plot scenarios.)

Which is why I find Seth Shostak's unwillingness to discuss any of this collegially, in open fora, deeply disturbing. It has riled up the contrarian in me. (And others.)  Even if I accept that the odds of harm from First Contact are low, I want to see this thrashed in the open.  And so do a growing number of dissenters.


What do I REALLY believe?  Of all the Fermi theories I've catalogued, the one I like best is (naturally) my own.  It is based on the one clear trait of our planet that violates the Copernican mediocrity principle... the fact that Earth skates the very inner edge of the sun's continuously habitable zone or chz.

(If Mars had been much larger, say Earth size, it would likely have had vast oceans, kept in Gaia-balance by a dense CO2 atmosphere.)

Because of this anomalous trait, Earth is probably very unusual for a life world.  The need to bleed off almost all of its incoming solar heat has necessitated an almost negligible greenhouse effect, with only trace amounts of C02. Hence making us especially fragile to the slightest manmade increase.

Does this translate into an abnormally rich Oxygen content and perhaps more land surface than most life-worlds?  Unclear.  But if one result were an Earth with exceptionally large continents and energetic air, then the implied galactic situation would be amazing!  There might be intelligence elsewhere, but vigorous, fire-using land creatures would be rare.  

Hence most ETICS could be sea beings, perhaps smart, even great artists and philosophers... but inherently unable to build starships or radio telescopes.  Isolated on their ocean worlds, they all could be waiting for someone like us to bring the first starships.  To give them the gift of contact.  And then to learn from their minds.

And, here’s the crux: it would pretty much have to be done physically.  In person.  A sudden switch from one steady state -- isolation -- to a new equilibrium of chatter and trade.  What a terrifically optimistic explanation for the Great Silence.  

That is, optimistic compared to most of the others.  It still depends on one thing.  Us, getting our act together.

I like this theory for another reason.  It offers, by far, the nicest potential destiny for our descendants.  We'll be the postmen, the envoys, the ship captains, the explorers... the cops.  With plenty of others to befriend, but nobody to push us around.  

It also offers a way for the galaxy to seem so empty, without actually being so.

Oh, if only...

Originally posted to David Brin on Sun Dec 16, 2007 at 02:20 PM PST.

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