Tuesday, January 26, 2010

Aliens - Why Haven't They Landed?

Reading about people like Frank Drake and the SETI organisation, and the Fermi Paradox, you get an impression of how much of a needle in a haystack we're looking for.  One of the points that the first article makes - but doesn't take any further than apply it to us - is the "going silent" problem we're experiencing.  Simply put, we had huge TV and radio transmitters pouring out signals into all directions and that meant that some signal from about the 30's onwards is still making its way outward at the glacial speed of light.  But now we have digital communication and the fields are shaped to provide the signal where it's needed, and not much is spewing out along the edges any more.

So our signal is reducing all the time, as seen from space.  Other alien civs won't be able to find us.  The problem is that "me me me me isn't going to be seen soon" without thinking about the consequences for any SETI efforts.

Part of my problem is not seeing or fully comprehending the Drake and Fermi equations for working out how many civilisations could be out there.  For example, are they saying the galaxy could contain the number of civilisations their equations come up with in all of time, a fixed time span, or what?  Not that it matters in practical terms, as you'll see.

Let's presume that there are 10,000 civilisations as predicted by the Drake equation with conservative inputs. let's further assume that Drake's equation means now, this instant, there are 10,000 civilisations.  Firstly, is this number the number Drake envisions as being communicative?  Or just any civilisations?  I'll assume that Drake meant any civilisations.


Now - we're "a civilisation" right?  And we spent, oh, 5 million years of that as creatures that wouldn't know a radio if they fell over it.  Only in the last 100 years have we been sending out a signal that reaches beyond the walls of the cave.  And now, after 100 years, our signal is flaring and dying.  So 100 years out of 5,000,000 years we're "live to air" as it were.  So for 0.00002 of our existence, we're visible, and then we're invisible again.


So out of 10,000 civilisations - even if they're all in existence right now - only 0.2 of them will be actively signalling right now.  In other words, there's a one in five chance that there's an intelligible signal from another civilisation right now.  There's also a much more likely four in five chance that there isn't.  Go with those odds.


Let's assume that there are in fact 100,000 civilisations out there.  It's entirely possible, given the wildly ranged results one can get from the equations depending on how conservative or how realistic or how optimistic one is with figures.  That's now improved our probability of finding a signalling civilisation to a one in one chance.  Not an ironclad certainty, you understand.  Just odds of one in one.  You're still in the realms of the Gambler's Fallacy, that odds are mathematically fixed ratios, which of course they aren't.  Even in a one to one probability, there will be times with a zero result, times with a result of two or even twenty.  


So while there's a probability of between one in one and one in five here, it doesn't mean that there has to be a communication now.


Furthermore, it doesn't follow that every other civilisation necessarily has the same progression as we do, and they may very well be combing our solar system with their ectoplasmic sauce bottle communicator and presuming there's no-one in the Sol system, either....   What if they feed on energy?  When was the last time you attempted to communicate with aliens by hurling food at them?  


So there's the small size of the window during which a civilisation might send a signal, there's the problem that the system is balanced finely on a line between us finding a completely concurrent civilisation that's also signalling at the exact time we're signalling and - more importantly - listenign for signals, and there's the problem that an alien civilisation could be using pink flamingo waves for all we know, and all our pink flamingos are actually going off every few minutes but we don't recognise this as an extraterrestrial signal, but instead thinking that's how flamingos are naturally.


And on top of that, we're now debating whether or not we should really be advertising our presence, whether we should put out beacons to get over the problem of our signature spectrum going silent or maybe just shut up and hope no-one else has seen us.  How can we predict if another species even wants to communicate, or would recognise our signals?  Maybe they don't want to put out a beacon once they've gone silent again.  Maybe as I said their beacon has been reverberating through pink flamingos for centuries already.  


Lastly, and a fave of conspiracy theorists, is that the aliens have already seen it and either contacted some people already, or are maybe even here already, among us.  And maybe we don't recognise them, and maybe they don't recognise us either.  


There are too many variables that we don't have numbers for yet, too many parameters that can profoundly change the results one way or another.  I'd say that an infinite Universe would have to spawn an infinite number of civilisations, but not necessarily all at once, nor necessarily all in the same iteration...  I'd love to be proven wrong... 

1 comment:

Tom said...

If we are talking so hypothetically, maybe we were the first sentient beings to have been created (with perhaps more to come), which promptly raised the issue of universal sovereignty that is yet to be resolved.

Only once it has been resolved would it be worth creating other intelligent life, once all the universal legal precendents have been set, with regard to who has the right to make the laws around here.

Or maybe we simply are the sole intellgient material creatures in the universe and that was the intent.

What about the possibility that "we" (mankind) are too busy looking for green martians without contemplating that there may be creatures that exist in the universe that we cannot detect using our various material detection devices (eyes, radio telescopes, whatever)?

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