[X] My Assistant

[deglr6328]

What is going on with SETI@home? I have in the past, (like many of the other users of this board I suspect!) run the SETI@home screensaver on my computer. I ran it for about 4 years and then uninstalled it. Not because I was fed up with not having an ET directly send to me personally a big "HELLO THERE" message, but rather because I saw little in the way of actual science being done with the SETI results we volunteers were all producing and because there seemed to be no plan for any kind of endpoint of the project in the future.

I recall seeing in a 2000 edition of Scientific American a plot of the already searched parameter space by SETI@home and it looked like most of our galaxy was searched and found empty obviously, of "type I civilizations" and higher. (ah. found it) Now, its been 6 years since then and we've since viewed ~97% of the observable sky from Arecibo at least once since the start of the project (~86% at least twice). Why are there no papers published on this result? It IS a significant result even if its negative one. Were there SETI papers published that I've just not seen? The SETI and SETI@home web sites are of very little help when looking for actual peer reviewed published papers that the projects have produced.

[Guest_Richard Trigaux_*]

I think this is an interesting topic, and that it fully deserves its place here as a science/technology concern, if we left besides any childish a priori in the style "life on other planets must/cannot exist" and any mockery about "little green men" or fear about "aliens".

Like many others I ran the SETI@home screensaver, but I abandonned because I have only an old slow computer which took too long to analyse one block.

The diagram deglr6328 found here summarizes the actual result of SETI searches:

-SETI cannot detect the equivalent of Earth at any distance, even very close (Barnard, Sirius)
-there is nobody at least than 100 light-years aiming at us powerfull radio beams. We know for long that the Arecibo radio telescope can communicate with its equivalent at about 5000 light-years. But nothing such was found.
-there are no type I civilization in our part of the galaxy.
-there is no type II civilization in our galaxy and local cluster.


But these results are still very incomplete, and just reflect a lesser blindness that previous studies. There are still plenty of place for many discreete civilizations and some larger ones. We can only rule out a powerful starwars-like galactic civilization sending a tremendous amount of energy in space. But we have still many possible scenarios:

-many civilization using "environmental friendy" radio communication
-they use laser communication instead, which are believed to be more efficient (thanks to a better focusing, or larger transmission rate).
-they use some quatum non-local technology, which cannot be detected. (I evoke this possibility in my fiction novels "The missing planets" and "Dumria")
-the civilizations evolve in a different way that just increasing technology power (I also evoke this possibility in a third novel to come, and many other possibilities can be imagined)


So, I think, we cannot yet say "there is nobody". We just tested a possibility. We are not with SETI as we are now with Mars, grasping to the last hope of finding life in very special places.


The fact that astrophysics predicts that there can be perhaps millions (or billions) of planets suitable for life in our galaxy, and the fact that we did not received any past visit or did not detected any radio communication, this is a riddle that nobody yet can answer.
It is the equivalent of the astronomy paradox of the black sky. The black sky paradox was solved with an element we could not predict (the universe has a finite past time) so I think some elements are missing to fully understand what we know today about SETI. Some possible hints:

-something we do not know makes civilisation much more rare than expected from astrophysics results
-we were very fast compared to others, and thus appeared among the firsts
-the assumptions describing type I or II civilisations are false
-they use other communication means
-they developed other type of behaviours than just colonialism/predation, and left planets evolve in their own way, so far as avoiding any interference, just like we are doing now with the last unspoiled tribes in Amazonia/Papua.
-they evolve in a different way than just increasing technology achievements in an exponential way.

Examining how life can emerge on a given star system is a matter of astrophysics and biology, but examining how civilisations (like ours) can last and evolve in the future is much more speculative and rather a matter of philosophy.

[helvick]

I'm also a lapsed SETI@home participant. I had a bunch of systems running under the name Dennis D. Gnome for the Ars Technica Team Lamb Chop group. I think I pulled the plug on the last one in 2002 after I'd clocked in 4331 work units (about 5 years of total CPU time). I had a chunk of systems in a test environment that weren't doing anything most of the time so SETI seemed like a good use for them.

Richard,

You left out out overt aggression as a possible reason for the silence. Even if intelligent life and space faring civilisations are common then even a tiny percentage that tended towards aggression\predation would create very strong evolutionary pressure that encourages "silent" civilisations that tend not to broadcast their presence. Greg Bear's "The Forge of God" and "Anvil of the Stars" set explores some of the possibilities that might result. This is a very pessimistic idea but one that I think is plausible.

There is also the "Intelligence Singularity" concept that Vernor Vinge explores in "Across Realtime". As the overall intelligence\information density of a civilisation rises the rate at which it increases also expands leading to a singularity effect. Since all bets are off at that point it is quite plausible that the resulting civilisation\intelligence might be unrecognizable and undetectable to us. Charlie Stross deals with similar ideas in Singularity Sky, one of the better Sci Fi books of the last year IMO. I'm not 100% sold on the singularity idea but I certainly think that it has merit as an idea beyond being a useful literary conceit.