[TED (2008) - http://www.ted.com/talks/susan_blackmore_on_memes_and_temes.html]
|[The (standard) Drake Equation]|
[BBC - http://www.bbc.co.uk/news/science-environment-11041449 ]
So it seems the realisation may be approaching mainstream consciousness: ogling the skies for alien peers is quite clearly pointless. Not because (the conditions for) life is necessarily rare (or because of any literal religious truth), but because life (e.g. humanity) will pass through this (SETI) phase in gynaecological evolution so rapidly...
From first radio broadcast to Matrioshka brain within 2 centuries (by my reckoning). On a cosmological timescale, biological life's coming of age will create the briefest of blips, detectable only by our local galactic neighbours, followed by it's star (e.g. our sun) suddenly disappearing. Waste heat radiation will be shifted right down towards background microwave levels. This is supposing something unpredictably odd (a transcendence of the known laws of physics) doesn't then happen, which it almost certainly will.
[Wikipedia - http://en.wikipedia.org/wiki/Matrioshka_brain ]
But what if it's not possible for a super advanced civilisation to 'sublime' (an Iain-M-Banks-ism), having attained the unimaginably lofty intelligence levels afforded by using an entire solar system's mass/energy to efficiently perform calculations (i.e. thinking)? (Or even if it is possible) This stellar scale engineering artificial life would be unlikely to be satisfied with utilising one system's resources, when all the whole universe is sitting ripe. Kilogram sized Von-Neumann probes could seed a whole new solar system. As each new island of mass (solar system) was converted to computronium, swaths of a galaxy would disappear (as far as external optical observers are concerned). The blob of darkness would balloon out at just under the speed of light. Entire *groups* of galaxies, around a single space faring seed-culture, could easily have vanished by now.
Humans, Earth and our solar system have been proved to be entirely un-special in location, so why should this 'Mediocrity principle' not also apply to our relative position in time (impossibly unlikely we'd be the lone first sentience)? A civilisation that happened to evolve 1 billion years before us (<8% of the time since the universe began) could have harnessed a volume greater far greater than the largest type of 'void' suggested by astronomical observations.
|[New Scientist blog - http://www.newscientist.com/blog/space/2007/08/colossal-void-may-spell-trouble-for.html ]|
To be sure, computer simulations of the universe's (gravitational) evolution can naturally produce the 'filliments' (and voids) of observed galaxy distribution; structurally, there is no need for intelligent life to have hollowed out these shapes. It could, however, explain the overwhelming percentage of 'dark matter' in the universe. But surely we'd have noticed if the *majority* of the universe was composed of alien technology??!!...
+ From 3rd Year Cybernetics lectures on information theory: a maximally efficient use of (serial) transmission channel capacity requires a coding system that will make it appear indistinguishable from perfectly random noise (unless one knows the coding algorithm). e.g. a digital signal with 50% '1's and '0's, where there is no discernible pattern left that could be represented more miserly. Earth could be bathed in a deafening cacophony of super-intelligent cocktail-party chatter, and still be helplessly solipsistic.
To stand a chance of detecting any civilisation more advanced than our own, they would have to be deliberately trying to signal us. Here on Earth, radio transmissions are rapidly decreasing in power while the coding density (e.g. switch from analogue to digital terrestrial television). Any signal lost into space is wasted energy: economically stupid.
Civilisations capable of sucking stars dry would easily have the power to create signals detectable by us from half a galaxy away. But imagine the situation when the amount of energy required to send a recognisable ping message to the our Arachibo telescope could instead be used to emulate a thousand human level intelligences, or 1M, or 1B, or a thousand alternative planetary civilisations even... why would they bother with a ludicrously expensive text message to a bunch of apes, when they could create perfect virtual replicas of them (or better) in-situe for the same or less resources!
+ Stephen Wolfram has been advocating hunting for aliens in the computational universe for some time: since his ground breaking work on cellular automata in the 1980s that showed how all the complexity of the universe can arise simply by iterating a deterministic algorithm.
|[Cellular Automaton (rule 30) meets Arecibo Message]|