Why we're still alone
Various SETI efforts -- the Search for Extraterrestrial Intelligence inside our galaxy, bien sur -- have been ongoing for thirty years, with no success yet. If there's intelligent life out there, we haven't been able to detect it with our arrays of radio telescopes and funky parallel-processing screensavers.
But what if we're simply looking in the wrong place? SETI projects tend to look for intelligent civilizations near stars, under the assumption that those energy sources are crucial to life. But in an interesting new paper (of which the PDF is here), the astronomers Milan M. Circovic and Robert J. Bradbury argue that any long-lasting intelligent civilizations will have intensive information-processing needs, and indeed may "be" information, having hit the Singularity and uploaded their consciousnesses into the aether. In that case, the authors suggest, alien civilizations would head out to the frozen outer regions of the Milky Way -- where information-processing would be easier for thermodynamic reasons.
As far as I can make it out, the argument goes like this: Any computer, in the act of doing computation, generates heat and needs to be cooled down with a heat reservoir. Obviously, a civilization composed of information will be doing a monster truckload of computation. Thus, as the authors argue:
In the ideal case, no energy should be expended on cooling the computer itself, since that expense should be added to the energy cost ... The most efficient heat reservoir is the universe itself, which far from local energy sources like stars and galaxies, has the temperature of the cosmic microwave background. [Italics in original]
If they're right, we need to radically rethink our SETI strategy.
Heh. I love that sentence. "We need to radically rethink our SETI strategy." I think I just won some sort of Blog Pompousness Award.
(Thanks to Robots.net for this one!)
Posted by Clive Thompson at June 21, 2005 11:39 PM
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There's something like this in Stephen Baxter's short story collection Vacuum Diagrams; an ancient civilization existing in a vast heatsink. I can't remember any more than that though. Sorry, that was a bit of a rubbish comment wasn't it.
Posted by: tomp at June 22, 2005 5:33 AM
Many years ago, Freeman Dyson suggested that a technologically advanced race, if it developed beyond the 'uranium barrier' (or any other self-destructive modes of behavior) would eventually learn to use all the energy of it's parent star. This could be accomplished by using all the mass of the planets in that system to build a large (heh, *really* large) hollow sphere to enclose their sun. Point being that all the energy produced by the star would be used to power the race's technology. We wouldn't be able to detect such a configuration as there would be no tell-tale signs coming from that system. Larry Niven's Ringworld was based on Dyson's notion.
There is another way SETI could be missing ILIOS (intelligent life in outer space) . . . not listening to the right signals. It's not the frequencies that are the issue, but how they are used. We (Earthlings) have ultra-wide band (UWB) or what is also called "impulse" radio, a technique that broadcasts information by modulating the timing between special radio pulses. To standard radio recievers, these signlas are indistinguishable from background noise. It is a very efficient mode of communication, which would be almost impossible to 'hear', let alone decode, especially at large distances.
Posted by: Tektrix at June 22, 2005 8:36 AM
Yes, tomp, the paper actually mentions many of the sci-fi novels that have discussed this possibility! The authors also talk about the Dyson-ring possibility and its problems. Good points about the frequency issue, Tektrix. Equally interesting is the possibility that we are in fact listening to the right frequencies -- and are in fact receiving an alien communication signal, as we speak -- but that we don't even recognize it's there, because it doesn't conform to our ideas of what information looks like.
Posted by: Clive at June 22, 2005 8:44 AM
Also keep in mind that our radio technology is all of about 100 years old - ultra wide band (UWB) is even younger.
In the grand scheme of things we're essentially firing pre-beta signals into the great unknown with no idea of what should be sent, nor what we should be looking for in return...
Posted by: garthbreaks at June 22, 2005 1:24 PM
Posted by: Clive at June 23, 2005 4:41 AM
Please to consider: maybe the universe is hostile ? Before we started broadcasting the entire human experience on tens of millions of frequencies, the Earth was an anonymous little lump. By 2005 we must be a pretty interesting anomaly for some vastly superior alien species to show up and investigate. I'm not saying the universe is out to get us... well, not the rest of you, but me, it's out to get me for sure- where was I?
Oh, the heatsinks... I just can't see any species giving up the pleasures of the flesh and no that's not xenocentric: aliens of advanced intelligence will have at some point in their history had to pick something up. If they did it once they probably needed to do it again and again... And the equivalent of Doan's Pills will be invented. The male of the species will whine for a back rub and try to turn it into a quickie. (And running and playing with puppies and all the crap that makes up life.)
When it is time for h.sap to evolve, I hope we can at least stay human.
Posted by: LumpyMartin44 at June 25, 2005 1:01 AM
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There's something like this in Stephen Baxter's short story collection Vacuum Diagrams; an ancient civilization existing in a vast heatsink. I can't remember any more than that though. Sorry, that was a bit of a rubbish comment wasn't it.
Posted by: tomp
at June 22, 2005 5:33 AM
Many years ago, Freeman Dyson suggested that a technologically advanced race, if it developed beyond the 'uranium barrier' (or any other self-destructive modes of behavior) would eventually learn to use all the energy of it's parent star. This could be accomplished by using all the mass of the planets in that system to build a large (heh, *really* large) hollow sphere to enclose their sun. Point being that all the energy produced by the star would be used to power the race's technology. We wouldn't be able to detect such a configuration as there would be no tell-tale signs coming from that system. Larry Niven's Ringworld was based on Dyson's notion.
There is another way SETI could be missing ILIOS (intelligent life in outer space) . . . not listening to the right signals. It's not the frequencies that are the issue, but how they are used. We (Earthlings) have ultra-wide band (UWB) or what is also called "impulse" radio, a technique that broadcasts information by modulating the timing between special radio pulses. To standard radio recievers, these signlas are indistinguishable from background noise. It is a very efficient mode of communication, which would be almost impossible to 'hear', let alone decode, especially at large distances.
Posted by: Tektrix at June 22, 2005 8:36 AM
Yes, tomp, the paper actually mentions many of the sci-fi novels that have discussed this possibility! The authors also talk about the Dyson-ring possibility and its problems. Good points about the frequency issue, Tektrix. Equally interesting is the possibility that we are in fact listening to the right frequencies -- and are in fact receiving an alien communication signal, as we speak -- but that we don't even recognize it's there, because it doesn't conform to our ideas of what information looks like.
Posted by: Clive at June 22, 2005 8:44 AM
Also keep in mind that our radio technology is all of about 100 years old - ultra wide band (UWB) is even younger.
In the grand scheme of things we're essentially firing pre-beta signals into the great unknown with no idea of what should be sent, nor what we should be looking for in return...
Posted by: garthbreaks at June 22, 2005 1:24 PM
Yeah, also very true.
Posted by: Clive at June 23, 2005 4:41 AM
Please to consider: maybe the universe is hostile ? Before we started broadcasting the entire human experience on tens of millions of frequencies, the Earth was an anonymous little lump. By 2005 we must be a pretty interesting anomaly for some vastly superior alien species to show up and investigate. I'm not saying the universe is out to get us... well, not the rest of you, but me, it's out to get me for sure- where was I?
Oh, the heatsinks... I just can't see any species giving up the pleasures of the flesh and no that's not xenocentric: aliens of advanced intelligence will have at some point in their history had to pick something up. If they did it once they probably needed to do it again and again... And the equivalent of Doan's Pills will be invented. The male of the species will whine for a back rub and try to turn it into a quickie. (And running and playing with puppies and all the crap that makes up life.)
When it is time for h.sap to evolve, I hope we can at least stay human.
Posted by: LumpyMartin44 at June 25, 2005 1:01 AM