How far away would other intelligent life be?

[ElPelado]

I don't know where to start. I want to say lots of things. After seeing the episode called "Are We Alone??" of the SPACE TV program yesterday, lots of ideas came to my mind.
So lets start:
We are searching now (or will be searching soon) for life in mars, Europa and titan as far as I know. We are also searching for planets orbiting other stars. I have heard of a big project of 5 space telescopes linked by lasers, each one 100 times more powerful than the HST to look for earth-like planets. We also have sent the voyager 1 & 2 probes. We have also have the SETI...
In my opinion if WE don’t find any form of life (dead or alive) in the next years (I don’t know how many years, maybe 10, 20, 50), we won't find it in the future. I said WE because we may not find but maybe there is extraterrestrial life, intelligent enough to find us.
WHY?
Because we are stupid.
WHAT MAKES US BELIEVE THAT IF WE FIND SOME KIND OF LIFE, IT WILL ALSO NEED WATER AND OXYGEN TO LIVE?????
We don’t now, but maybe, there are extraterrestrial beings that need the hot whether of mercury. Or the hot whether if Venus and its clouds. Or the cold whether in Pluto. Or the gases in a gas giant. WE DON'T KNOW IT!
I know that we have to start from something, but maybe we (and the animals) are the only beings that need water and oxygen for life. The earth is on a perfect place and has all what life needs to start... but only life as we know it. As I said, maybe another kind of life needs the conditions that we find in mars, or in Venus or mercury.... we haven't even started looking for life!!!! There are millions of stars inside millions of galaxies inside millions of clouds of galaxies inside this universe (maybe there are also parallel universes, we don't know yet).
We are also looking for primitive life forms, but maybe we are the primitive life form. We have been using the radio for more than 50 years, that means that in a sphere of 50 ly around us, if is there somebody, they must already heard about us... but maybe there is nobody, or maybe they aren't intelligent as we are.
In my opinion we have to start thinking that we, and everything on this planet, are unique. And we have to start looking for other kinds of life. I heard that in ocean volcanoes, where the temperatures are higher than 100°C and there is almost no light, we have found life. So maybe if we sand a "swimming" robot to Europa we will find something similar. But we need also to send probes to land in Venus and mercury (and to be there more than just minutes). Or maybe to Io, why not? We don't know where we can find life. We think that life exists only in places with water. But this may not be true.
We have to "free our minds" and start looking for something else than water and ice. Or we just won't find anything.
That’s my opinion.


Pd: I thought about more things to say, but I don't remember them now.

[Guest]

We are also looking for primitive life forms, but maybe we are the primitive life form. We have been using the radio for more than 50 years, that means that in a sphere of 50 ly around us, if is there somebody, they must already heard about us... but maybe there is nobody, or maybe they aren't intelligent as we are.

Not so. Broadband transmissions like radio and TV spread their energy out over a wide range of wavelengths, making them far more difficult to detect than dedicated SETI narrowband transmissions. Even very large radio telescopes (larger than any we have today) would have great difficulty detecting radio/TV transmissions beyond the solar system. Radar signals are visible to a greater distance because of their narrower bandwidth, maybe up to a substantial fraction of a lightyear. By contrast, even a small radio telescope could stand some chance of detecting a powerful, yet very narrow band transmission made from tens of lightyears away, which is why SETI receivers aim for narrow bandwidths.