This question already has an answer here:
first of all I'm not sure if I should post this here or in the astronomy stack. I think biologist are more likely to answer my question. To make it short:
Why when looking for any sort of life on other planets, we keep looking for similar conditions we call "life friendly", like nice temperature, oxygen level, pressure etc...
Is there some rule in biology that says life can only exists under these conditions? Why nobody supposes that evolution did not have enough time yet on our planet to generate other living mechanisms, and that on other planets even if the conditions are not suitable for us, there might be something well evolved through time there. After all if we can conceive electric robots that can survive to radioactivity and to high pressures and temperatures, why nature shouldn't be able to?