a reply to:
alfa0152
The ideal world for us to find would NOT be a planet with an already existing biosphere but one that we could seed and in short order biochemically
alter to become suitable for human colonization, this may however take a long time so a solar system with suitable raw materials for long duration
space habitation such as asteroid belt material etc would be an added bonus.
But a planet that is already host to native life no matter how suitable and similar the conditions may already be is a very bad idea for human
colonization, one we may be seen as an aggressive and predatory expansive species by any other Sentient life that could be watching us as we expand
into the universe, something they would not be as likely to think if we were taking empty world's and converting them for our use.
Also we could hinder, alter or harm the natural evolution of alien biospheres through such aggressive colonization but if we are the one's actually
creating new earth like world's from barren but suitable planets then that would not be the case as our descendant's on those world's could very well
claim that they are then the true native species of those converted world's.
But if we leave colonization and human habitation assuming that some day we learn a method to travel to these distant worlds perhaps by mastering
inter-dimensional travel and taking short cut's across the universe that way then any scientific non colonization missions that may seek biological
unique specimens and samples from living worlds (Some of which we may then cultivate ourselves and make use of) and cataloging there biospheres may
find very earth like planet's and also very unearth like planets, we assume that life would be carbon based and roughly similar but that is not a
necessity and life could have completely different chemistry's even on planet's in what would be regarded as the Goldilocks zone for our form of life,
some of these other form's of life would perhaps find some of our own uninhabitable world's suitable for them and if we were to meet such a species at
a similar level of technology and if we could exist together and cooperate with them could perhaps co colonize the same solar system's but inhabit
planet's in different belt's around there respective sun's.
Some plant analogues may be green, blue, purple or even black and the spectrum of there sun would also play a part in that, we may come across
planet's almost identical to the earth were despite the similar atmosphere the sky could appear green or purple or orange depending on the exact
spectrum and sequence of star they are in orbit of.
What the alien's if we meet other sentient life would look like is rather more interesting, we may meet races that more or less fit the same form as
we have but other's could be completely different, there are many way's that the EYE could form and achieve the same functionality, many way's that
the hand could form and achieve the same functionality and many way's that a creature with or without a spine analogue may achieve intelligence and
colonize there own planet before leaving it to explore there own solar system's and beyond.
But the biggest worry is if we should encounter a so called predator civilization, these are society's that if they exist actively eradicate other
sentient life for reason's of there own but probably to maintain there own dominance - if they exist and our biggest hope therefore would be to find
and get in with a group of advanced cultures that protect emergent sentient races in the Galaxy and beyond from these predatory races (if they
exist).
Both predatory and protective species may have passed our way in the past, we may even owe our very survival and existence to protective races that
may have taken us under our wing while we were evolving but then followed a hand's off approach for the majority of our development, also if some
claim's and I for one think they have substance that there are ruin's on the moon and mars are true then our solar race may have been almost destroyed
at least once already by a predator race, or a previous race WAS destroyed - but were they benign themselves?.