[recursivecaveat]

Earth is 4.5 billion years old, but the milky way is only 105 thousand light years across. So even if you assume an earth like planet couldn't have formed any earlier than ours, other intelligent life in the galaxy only has to go through the geological processes and evolve a tiny tiny fraction of a percent faster to have tons of time to send all the signals they ever want. Nearest other galaxy is only a couple million LYA which ain't too bad either.

[thomassmith65]

My guess, again based on the lack of cosmic signals we have detected, is that intelligent life is rare enough - at this age of the universe, at least - that we have no company yet in the Milky Way. That leaves a lot of room though - there might already be simpler forms of life.

But I won't go to the mat arguing my impression; we only have evidence from one planet to go by, so any view here lacks empirical evidence.