500 planets isn’t even a drop in the proverbial bucket. I have no doubt extraterrestrial life is rare, given the conditions needed for a planet to be in the habitable zone. But impossible? If even only one out of a hundred million planets is capable of producing life as we understand it, that still leaves 40 or 50 likely candidates in the Milky Way galaxy alone.
There is, of course, also the possibility that life has evolved in ways we haven’t fully grasped. Don’t want to head off into Star Trek land, but we do have bacteria right here on Earth that feed on jet fuel and other exotic materials. It’s not impossible that there is some form of bacteria or other primitive life to be found in the seas of Titan and several other moons of Jupiter and Saturn.
>>> Don’t want to head off into Star Trek land, but we do have bacteria right here on Earth that feed on jet fuel and other exotic materials. <<<
I must adjust my tricorder to read silicon-based lifeforms, Captain.