After reading Amir D. Aczel "probability 1" and
Paul Davies "are we alone" I kind of had expected that damn
signal by now. But ok - now Paul Davies is out there
with a new place to look for the signal...

   For more than 40 years, mankind has been
using radio telescopes to pick up signals from
alien civilisations.
   And so far the silence has been deafening......

   Which might not be that much of a surprise.
After all, Alien civilisations could be million of years ahead
of us. Either they should continue to send signals
in our direction for aeons, hoping that
we would one day build a radio telescope. Or they
have only transmitted sporadically, in which case we
have an about zero percent chance of tuning in
at the right time.

   So, if the ETs really want to contact us it would be
much better for them to leave some kind of superstructure
on our planet or in its vicinity - which would then
"phone home", when we are evolved enough to be interesting
(2001, A Space Odyssey).
    Certainly a nice idea, but it also
has its problems - such artefacts on a planet surface
might be overlooked (by the dummies) or eroded away over the aeons.
    A better solution would be to have messages inserted
into something that is small, cheap, self-repairing and self-replicating.
And which is always close to the species (dummies)
you want to contact. Something that keep copying the information
over immense durations and despite whatever unforseen environmental
hazards might pop up.

    And we have such things - they are called cells!
So, according to Apollo astronaut Rusty Schweickard the place to
look for messages from ET is in DNA.
    Obviously, there are mutations in the DNA - so ET
would probably incorporate messages in parts that are highly conserved.
Unfortunately, such parts are normally essential coding parts
that control the most vital parts of an organism.
Inserting messages in non protein coding parts - socalled "junk DNA" -
have a better chances of being not harmful for the organism.
But such parts are also likely to accumulate lots of mutations
over the aeons, that would destroy the message?
Fortunately, highly conserved sequences of "junk DNA"
have recently been discovered!

    So, that could be a nice spot to locate the primer for
how to go online to the Encyclopedia Galactica.

-Simon

Simon Laub
I have set up a blog on this - just in case:
http://etmessage.blogspot.com