Re: SETSIs (was Re: seti@home WILL NOT WORK)

Robert J. Bradbury (
Sat, 10 Jul 1999 00:51 PDT

> Dave Sill <> wrote:

> > So taking Ockham's Razor, which of the following would you choose:
> Occam's Razor is great for playing the odds, but it doesn't prove anything.

But the entire discussion revolves around what do you devote your (computer) time to, given your perception of the odds of success. I'll admit that many people may care nothing about the odds and probably care much more about a self-perceived "cool" use of their computer.

> Or, as has already been pointed out, they could have been farther away but
> further advanced: e.g., 200 light years away, 200 years ahead of us.

I've responded to this. If they are at the level where they can waste away energy on continuous omnidirectional signals *or* have the technology to "see" us (200 years ago), they are most likely very near or post-singularity. It is worth noting that while we are making efforts to "listen", we have done very little intentional "transmitting" (due to the requirement for using valuable radiotelescope listening time as well as expensive power). Since pre-singularity economics are pretty ruthless, I would expect this generally to be the case for aliens (though I could see their being rare exceptions, e.g. wierd tribal customs requiring talking to the "gods" in the sky, etc.)

For the record, Sullivan et al (Science 199:377-388 (1978)) showed that: - An Arecibo-size antenna could detect UFH TV out to 2 light-years and the U.S. BMEWS military radar out to 20 ly. - The Cyclops array (which was never built because the cost was something like $1 Billion+, could extend these ranges to 25 and 250 light years.

So, the implicit assumptions in SETI@home would seem to be that (a) they are very close; or
(b) they are devoting a lot of power to talking to us

> > of Earth-like planet supporting stars in 100 cubic light years
> > into the Drake equation
> Er, shouldn't that be "the number of Earth-like planet supporting stars in a
> sphere of 100 light years radius"? More like 31000 cubic light years. and
> that's not even taking into account the previous point regarding the 100 ly
> number.

That's what I get for doing these things late at night. How about 4 pi(100)^3 / 3 which works out to about 4 million ly^3. The general point would be that most people plug 200 billion stars (in our galaxy) into the Drake equation (a volume of something like 10^15 ly^3) and say "they must be out there". The SETI@home receiving antennas only have the ability to listen to a small fraction of that (order of 1000 stars if I'm doing my math right and we assume 100 ly detectability which rests on the assumption that they are transmitting at a power level significantly greater than our level).

> Sure there is: RC5 and GIMPS are two, there are many others.

I was refering to games which detect ETs/SIs.

> Which organization is accepting donations for that? If there isn't one,
> why don't you form one?

If I can't persuade the SETI/2MASS people to look seriously at this, that would be the next logical step.

> No you don't. You can ignore the SETI people completely.

It depends which SETI people you mean. People like those at the SETI Inst. or the general population running SETI@home.

The detailed calculations like those regarding radio detection, or building 1,000,000 channel receivers, or designing programs to unscramble signals where the encoding method is a mystery, are not simple. The SETI Inst. and related groups are very good at what they do. It would be silly (at least initially) to duplicate their work. It makes sense to try to enroll them in looking at things a little differently in light of knowledge I (& many Extropians) may generally accept, but they are unaware of.

If they see the light, then they can modify their public education efforts and computer time allocation system to handle both perspectives. Only if that fails, would it make sense to try and create a competitive effort. As I've said before, I think the probability that we currently have datasets to detect SIs is low, it may be only slightly better than the radio-SETI data. The current collection of SETI people are better equipped than I am to make the proposals to to other astronomers that would be required to get the telecope time to get better data!

This forum serves as a good one in which to flush out how people will react to some of the claims so I'm better prepared to deal with the bioastronomers & hard core SETIists.