Jeffery wrote:

Interstellar travel is impossible since it would take centuries or
millennia to reach other stars. Aliens are not going to spend 1000
years traveling to our star, doing nothing but making a B line to our
star, when from their point of view,


Typically this assumes set answers to prior questions that failed to
have been asked, and admit other answers. Do aliens need to travel to
our star to become observable ? Suppose the contrary. What are the most
potent beacons of aliens existence we might imagine ? My entry is
"busting stars". Suppose that after a few centuries of detailed
observations of patterns of stars exploding in "nearby" galaxies, the
records shows that an ever-expanding proportion of explosions fits a
model of war fronts between intelligent races ?

I am sure this could make a nice DOE-subsidized paper ! "The Cosmic
Prisoner's Dilemma" could hypothesize an intergalactic arms race, s.t.
most of the intelligent races of the Universe end up learning a
compelling technology and survival strategy by observing their impact on
patterns of star explosions in other galaxies... after a millenum of
observations.

Absolutely no one in their right mind would suggest that Earth was the
only world with life in the entire Universe.

I don't agree with this. Under the premisses, our being alone *is* a
possibility that stands out both because it is (in some sense) the
simplest. What probably deserves scorn is the notion that we would ever
be able to *prove* that we are alone.

Regards, B.