Hi All

LJK's SETI optimism is a reasonable position, as is the case for SETI pessimism. Here are a few of my quibbles with what he wrote...

...we're still too young and lacking in knowledge to truly understand what we see in the Universe and how to go about the right way to find ETI.

[maybe. Perhaps neutrino beams or gamma-ray lasers are the way to communicate - if so then no one is trying to talk to us. There are no beacons within ~ 150 light years of us amongst the 1,000 Sol-like stars in that range... that's the conclusion of Project Phoenix.]

Up to this point we have been primarily guessing and making mainly sporadic efforts to look for alien life beyond Earth. Forty years in a galaxy that is 10 billion years old is virtually nothing. Even places like the SETI Institute won't be searching for signals full time untiil later in this decade.

[Maybe so. A recent discussion points out that SETI has looked at a tiny, tiny bandwidth compared to far more useful frequencies. Also Frank Drake has rightly pointed out that within 50-100 years Earth won't have any interstellar spanning radio leakage. ETIs have to deliberately target us if they're out there and can be heard]

Plus it is the height of hubris to think that ETI, especially really advanced ones, are just so eager to communicate with the talking monkeys with car keys on Sol 3.

[I think that might be true, but it is also a bit of an old line that ETIs will have hang-ups about evolutionary origins - what's wrong with coming from monkeys? Or starfish? Sponges? Vurkuls?]

The Milky Way galaxy alone is vast, with 400 billion stars spread across 100,000 light years.

[The actual estimate is just ~ 100 billion stars, but it has been exaggerated so ~ 400 billion is something of a truism]

Half the estimated Earth-like planets in our star island are several billion years older than our planet (this comes from Geoff Marcy).

[Charles Lineweaver is his source - his metallicity model neglects things like supernova and higher GRB frequency in the past, so while most terrestrials are older they were also too soon for ETIs to survive. Earth probably got whacked a few times prior to our current quiet patch of cosmic time.]

So what makes us so special, other than we have spent our whole history isolated on one planet,

[didn't everyone, prior to Galactic Empire? So where are They?]

we're just waking up on a wider cosmic scale, and we still think the whole place was made just for us.

[which is true if we are alone - rather it will be ours, if we're alone...]

--- I'm not writing off SETI just yet. But I don't think there will be many ETIs, or if there are we will all be roughly at the same point of development, plus or minus a few billennia. But of course a million years is all it takes to conquer the Galaxy at sub-light, so where are They? Greg Matloff has proposed that They are living quiet lives in mobile habitats 'hidden' in the Kuiper Belt... perhaps he's right? Alternatively they have quietly permeated the Galaxy but missed our little corner. But why no Dyson spheres?

Adam