scott wrote:
>> How about the fact that the stars of the universe are all red-shifted 
>> the farther they get from *us*?
> 
> Once you have the information about the surrounding stars, isn't it 
> quite trivial to show that from the point of view of *any* star, all 
> other stars are red-shifted more the further away they are?

Only if you assume they're red-shifted *because* they're moving apart.

You're assuming that if you're in a distant galaxy and look back towards 
ours, ours too will be red-shifted, rather than blue-shifted. If, on the 
other hand, we were in the middle of the universe and time just happened to 
run fastest here, then we would be blue-shifted compared to other galaxies.

> Why the assumption that any intelligent lifeform would be broadcasting 
> radio signals for any significant time in its existence?  To me that 
> seems silly. Earth has been broadcasting radio for 100 years out of 4.5 
> billion, maybe we will continue to do so for another 10000 years until 
> we find something better?  Those timescales are tiny compared to the 
> variation in ages of other stars.

There's lots of discussion about what we should have found, including von 
Neumann probes and such. I think there are a lot of good arguments that (for 
example) given what we've accomplished in the last 100 years, someone who 
evolved intelligence only one billion years ago should already have 
colonized the galaxy.  The big numbers work both ways.

> Also, really can you detect the radio signals from Earth more than a few 
> light years away?  Isn't the signal going to be incredibly tiny and 
> virtually impossible to detect?  And that's just a few light years, what 
> about the other planets billions of light years away?

That's the argument, yes. It's certainly not conclusive. We can tell what 
planets have atmospheres and water from here, only 100 years after steam power.

-- 
Darren New, San Diego CA, USA (PST)
   Yes, we're traveling together,
   but to different destinations.

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