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From: nospam@de-ster.demon.nl (J. J. Lodder)
Newsgroups: talk.origins
Subject: Re: New SETI search
Date: Wed, 4 Sep 2024 21:50:32 +0200
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Bob Casanova <nospam@buzz.off> wrote:

> On Tue, 3 Sep 2024 21:48:53 +0200, the following appeared in
> talk.origins, posted by nospam@de-ster.demon.nl (J. J.
> Lodder):
> 
> >Mark Isaak <specimenNOSPAM@curioustaxon.omy.net> wrote:
> >
> >> On 8/26/24 10:24 PM, El Kabong wrote:
> >> > RonO wrote:
> >> > 
> >> >> A group is using the Murchison wide field array to monitor for super
> >> >> civilizations in other galaxies.  The civilizations would have to be
> >> >> super advanced in order to generate the 100 MHz signal that they are
> >> >> scanning for.  Huge amounts of energy would have to be channeled into
> >> >> transmission of such signals.  Would we ever expend such an effort to
> >> >> tell someone in another galaxy that we exist?  100 MHz is in the middle
> >> >> of the FM radio band, but in our expanding universe what would have been
> >> >> the frequency transmitted by any one of the 2,800 galaxies scanned in
> >> >> the survey?
> >> >>
> >> >> https://www.sciencedaily.com/releases/2024/08/240826131354.htm
> >> >>
> >> >> Ron Okimoto
> >> > 
> >> > Previous searches at Aricebo and other sites looked for
> >> > alien signals at 1420 Mhz.  They picked that frequency
> >> > because it is a hydrogen line.  The thinking is that
> >> > aliens would more likely broadcast there than an
> >> > arbitrary frequency.  It never made sense to me because
> >> > the signal will be attenuated by any hydrogen lying in
> >> > the path, and because if you tune in to the hydrogen
> >> > line, you'll find... hydrogen noise!
> >> > 
> >> > Maybe space aliens will broadcast on 100 Mhz because it's
> >> > a nice round number?  Then again they might have 3 digits
> >> > per hand and use a base-6 system and think 60.466176 Mhz
> >> > is a nice round number where other hexadigits would
> >> > listen.  In any case you have to pick a frequency
> >> > somewhere.
> >> > 
> >> > The article you cited does link to an article on a
> >> > previous survey done in 2020, but it doesn't mention the
> >> > frequency.
> >> > 
> >> > If the aliens transmit from a large phased array like 
> >> > MWA, they could transmit a large effective power within
> >> > the beamwidth, without actually transmitting huge power.
> >> > But the beam has to be aimed in our direction.  Maybe
> >> > they send signals periodically in every direction.
> >> > Similarly the MWA has to have its array pointed in the
> >> > right direction at the right time.
> >> > 
> >> > The chances are slim, but worth trying.
> >> 
> >> If I had vast technological resources and wanted to send an "I'm here"
> >> signal to unknown aliens over potentially vast distances, I wouldn't
> >> generate light. That would take way too much energy, especially if it
> >> was broadcast widely. Instead, I would rig up some opaque sheets and set
> >> them orbiting around a star, with gaps in places so that anyone watching
> >> from the plane of orbit would see a dit-dah message spelled out 
> >> repeating every 6 (of our) months or so.  It would work only on a fairly
> >> narrow plane, but at least it's better than a laser pointed at a single
> >> target.
> >> 
> >> Is SETI set up to look for anything like that?
> >
> >Why would they waste resources on that?
> >Any search for exoplanets will find such a signal.
> >As a matter of fact somthing very much like it has already been found.
> >(six planets around the star HD 110067
> > locked in periodic perfect 3/2 and 4/3 resonances)
> >No design involved.
> >
> True. But one could make it arbitrarily complex, with
> essentially zero probability of it being natural.

Have you seen 'The Ringworld Engineers'?

> >> Of course, I would never do anything to attract strangers until I was
> >> more than confidence that my technology could overpower any hostile
> >> aliens I might attract. If possible, I would set up the signal several
> >> hundred light-years away from concentrations of my species' population.
> >
> >You are American, I presume?
> >
> Why do you assume that?

No need to presume, in your case,

Jan