Radi Khrapko wrote:

An answer to the Fermi's question, `Where are they?', is
presented.


Strictly speaking, it is answering a different question,
eg "why don't we observe them", implying the original one is rhetorical. I
don't agree that "Where are they?" is rhetorical. It's really not like there
wasn't a lot of places where we could imagine "them" to be.

An interesting er, counterweight variant, is the belief that in a small
billion years, dozens of the closest galaxies of the Universe will be ablaze
with signs of life from end to end, but just right now or about, billions upon
billions of intelligent planetary civilisations reach the step of willfully
conquering the scales upward to make that happen, while being yet at 99.99%
outside of each other's cosmological horizon.

This is a radical but beautifully simple hypothesis, the "Universal Biological
Clock Diagonal Hypothesis". Jingle : "God grows SIGNIFICANT Mathematicians
Everywhere in the Universe in an Amount of Locally Elapsed Time since the Big
Bang that's Unexpectedly Uniform and Precise"

.... and presumably (slightly ?) above our own universal age

Cheers, B.