Good thread
frogwoman I think it would all depend on how developed life was. If we find some amoeba like beings in a lake on a moon somewhere it would be exciting but not life changing for earthlings.
However if we got a sign of a developed intelligence somewhere out there perhaps more developed and more intelligent than us, we could feel threatened, how would we judge their intentions?
How likely is it that life developed / evolved on planet earth and nowhere else?
Are there no other planets circling suns in the goldilocks zones where the environment could be conducive to life? It seems likely that there are many many millions or billions of suitable planets out there.