Re: Alternative life forms
"The universe is probably teeming with life but in forms that we do not recognize or understand or are capable of understanding from a chemical/physical point of view."
On the other hand every time we've assumed our conditions are "special", we've been proven wrong.
Water and carbon are some of the most common items out there in the universe. Most other possible chemistries are difficult without extreme (from our point of view) temperatures and would be heavily poisoned by the presence of either of the above. That's not to say they're impossible, but carbon-based life is the most likely form. It could be anaerobic or aerobic but it's a fairly safe bet to assume that within a few billion years of anaerobic life evolving on any planet with access to sunlight some species will develop a way of harnessing the light energy and splitting water in the process, generating oxygen in the process (which will kill off virtually everything else, as happened on earth)
Seeing an oxygen signature in any planetary atmosphere is a telltale indication of life "as we know it" - the "plants" may not be green (that's an artifact of the light frequencies available to the first chloroplasts trying to get light after the blue-green and red algae had hoovered up most of it), but it would be carbon-based, water-splitting and light-eating.
Carbon-based anaerobic life would virtually always inevitably give way to aerobic life due to the evolution of oxygen-generators. The harvesting of available "free" energy (much easier to deal with than thermal energy) makes this almost certain over evolutionay time periods. Even if the results are random when you throw the dice, eventually you will throw 5 sixes (Yahtzee!) 4 times in a row. It's only a matter of "when" and nature is endlessly patient.
Biting the hand that feeds IT
