wrote on 20/07/18 04:32:
... will find younger rather than older civilizations on planets of nearby

star systems ...

We can not, nor will we ever be able to determine what's on any
planets in other star systems.

DO THE SIMPLE MATH !

Distances between stars are far too great for that type of
interaction. Telescopes and other like devices are nowhere near
capable of dirrectly detecting any such planets.

Which is exactly why the Astronomers have detected well over 3,000
exo-planets ....

"As of 1 July 2018, there are 3,797 confirmed planets in 2,841 systems,
with 632 systems having more than one planet.[6]"

https://en.wikipedia.org/wiki/Exoplanet

--
Daniel