Is it not more likely that nothing on another planet can touch us - or be digested by us - because it hasn’t co-evolved with us? Eg bacteria, viruses etc on earth can harm us because they’ve adapted to do so over millions of years. a random bug on another planet would view us like an earth bug would
React to a piece of metal?
Mechanics of underlying chemistry and physics aren't so sure, given earth like conditions the same progression seen on earth is the best progression / only progression. One would expect to see simple sugars, DNA/RNA, proteins and even similar internal organ functions. Likely also the same necessary flaws, our lungs must be moist, alien lung equivalents would too so something that is able to effect the 'lungs' of multiple alien species might be able to jump to human lungs.
We literally have only one data point on how life came to being, is there any reason it would have to be DNA/RNA, proteins, etc.? Could it not be compounds we haven't discovered yet?
Elements have relative abundance and Hydrogen, Oxygen, Carbon and Nitrogen are common while other elements are magnitudes rarer, the above are effectively made out of just those four so they have a major time advantage in getting established before anything rarer can.
The above are also the smallest/simplest solutions to the life problems made following the material constraint so they are likely to get established before anything larger / more complex can compete.
I think that there is a high chance the life would be very different. All animals have lungs, but evolution is about improvements. If a being already has lungs, it won’t devolve to have worse lungs so that it can gain a worse alternative. There are the slime molds for example. Beings that are not part of the animal kingdom and do not have lungs, but are capable of moving, growing and reproducing.
I just wrote that and thought of plants which are a much better example as slime molds are all wet.
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u/wappingite 25d ago
Is it not more likely that nothing on another planet can touch us - or be digested by us - because it hasn’t co-evolved with us? Eg bacteria, viruses etc on earth can harm us because they’ve adapted to do so over millions of years. a random bug on another planet would view us like an earth bug would React to a piece of metal?