How far outward can we rule out intelligent life?

[Alltimegreat1]

I just disovered today the term "radio bubble," which extends 110 LY from the Earth in all directions. This bubble around the Earth contains 15,000 stars.

 

[nikkkom]

I see no major conflict in our position. I was addressing a special ability (flight)practised by insects 10-15 million years ahead of the appearance of birds. Watch the Robert Hazen lecture, which I linked in previous posts. I see no major conflict in our position. Robert Hazen proposes that biochemicals are abundant in the universe and that the Earth is not a special planet, but that it requires only an average rocky planet with oxygen and water to eventually (inevitably) produce bio-chemistry and the beginning of bio-molecules, which then evolved into complex bio-organisms. The exact times are not important, all that matters is that complex bio-molecules almost inevitably will form, given enough time and under the right conditions.

My point is, average "enough time" for appearance of differentiated multicellular life may be very large. Say, much larger than current age of the Universe. It's possible that we are a very unlikely statistical fluke.

"Something is bound to eventually happen" does not equal practically meaningful probability above zero. Example: a neutrino can scatter off other particles via gravitational interaction. But its probability is so astoundingly tiny that even if human civilization will spend the rest of eternity (until heat death of the Universe) trying to detect such an event, it will never be seen.

 

[Dr Barkus]

Let's assume there is a planet out there with life equally intelligent as humans that is putting in the exact same amount of effort to detect alien life that we are. Their science and technology also developed in line with human technology. Given that we're looking and they're looking, what is the closest this planet could be to us given that we don't know about them (yet)? Any guesses?

One overlooked question is could intelligent life evolve on planets that are unsuitable for us? If it transpires that only Earth type planets can evolve intelligent life then there maybe only a few of these per galaxy hence the quietness

 

[|Glitch|]

One overlooked question is could intelligent life evolve on planets that are unsuitable for us? If it transpires that only Earth type planets can evolve intelligent life then there maybe only a few of these per galaxy hence the quietness

intelligent life can certainly evolve on planets that are unsuitable to humans. Intelligent life has evolved on Earth in environments that are totally unsuitable to humans, so why not elsewhere?

 

[Rx7man]

I think the timeframes we're looking at here are SO NARROW.. we've had technology for what.. 100 years?.. Perhaps in another few hundred years we'll have wiped ourselves out.. If that is a pattern that happens on other planets that could or have had intelligent life, the timeframe is so small there's a good chance we'd never witness it, even if we were looking in the right place.

And the definition of intelligent life seems a little narrowminded in itself.. Perhaps if we defined it as radio-capable intelligent life it would be more accurate. For billions of years we've had intelligent life on earth, though it never broadcasted any radio signals.
For the Fermi paradox.. I think we ought to worry more about what perils we're setting ourselves up for at our own hand than the slight chance that an alien will pick up our signals and come destroy us... Yes, it makes for (debateably) good sci-fi movies, but trivializes what we're doing ourselves