The reason people keep bringing up ridiculous notions about
aliens is their failure to grasp history on an astronomical
scale. This is especially the problem of the SETI-type chanting
yoyos who keep bringing up Drake's equation to say that other
civilizations must exist but be "improbable" so that we haven't
"contacted" them. In their ossified brains they've got some
small notion of the many billions of stars which are in our
galaxy, but not of the billions of years which lie in its past.
We will start with a very simple assumption. The galaxy as we
see it is the most probable way for us to see it. And from this
assumption we will recover that aliens (other advanced
technological species) do not currently exist in our galaxy and
will never exist. To start off with, how long does it take for
an intelligent species to rise and colonize the entire galaxy?
It takes roughly 100,000 years. Because the galaxy is 100,000
light-years in diameter and civilization arose on Earth a mere
10,000 years ago. Even under the m