Re: New SETI search

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.