- #1
DaveC426913
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I'm writing a science fiction short story about an ocean world with indigenous life, colonized by humans, and I want to check some of my "facts".1.
Given the possibility/assumption of panspermia, spreading hydrocarbons and possibly even simple enzymes between systems, is it plausible for a habitable planet to produce complex life forms that share at least marginally metabolizable compounds with us even if they didn't develop the same DNA?
(I find it stretching the limits of plausibility that an ecosphere on a distant planet would use DNA - even if it started with mostly the same components as us. It might be similar in function to DNA but I find it hard to believe DNA is the one possible molecule that can develop complex life.)
How similar (and thus, how less plausible) would an alien ecology's chemical structure have to be to be marginally metabolizable by humans (if not wholly nutritious)? Alternately, how dependent on the DNA molecule itself are the proteins we need for nutrition?
I know we need carbs - but they're pretty simple. I know we need proteins but they're super complex and, in my opinion, very unlikely to match ours.
But what if the breakdown could be helped along? Say, a chemical additive that would break down alien proteins enough that they were usable by us?
Maybe it would only have to be for short durations i.e.a trip into the wild - as long as they got back on human food in some reasonable time-frame - or could at least supplement their diet with human food for the duration.
Assume technology and bio-chemistry is a century ahead of ours. Assume colonists have had some decades to work on the problem.2.
How difficult might it be for an alien organic critter to emit and detect radio waves? (How/why they evolve this - and the energy budget it might cost - might be another matter.)
Most Earth marine species can detect electricity, and some, such as eels and catfish, can produce it. Is it a big leap to go from electrical pulses to producing bio-chemo-electric sparks (spark-gap radio?), and then to fine-tuning them to produce primitive radio waves? Not hi-rez, like sonar, but they might be able to communicate or sense each other across some distance.
3.
How plausible is a super-Earth ocean world with a goldilocks climate but without the crushing gravity? I was hoping for a world about 1.5 times Earth, but less dense (say, 3g/cm^3), so that its gravity works out to Earth's or less. I looked up ocean worlds and it seems there is an upper limit - that of a small moon. Much larger and the barrier between vapour and liquid and solid seems to disappear. (I guess this plot detail isn't critical. I wanted a vast ocean world but it could simply be an ocean worldlet.)
4.
Can such a world hold on to its atmo? Or will it be stripped away like Mars? Ideally, a thick atmo is better. Looking to build a world where flying is easy.
5.
I'm looking at a primordially radial body plan - like jellyfish and diatoms - as opposed to bilateral. The first life might have been 3-sided, but later mutations produced 4-, 5-, 6- and 8-sided forms, creating the various phyla. Might it be more plausible for mutations to double a symmetry-axis, versus add a symmetry-axis? eg. 3>6>9 versus 3>4>5. Any reason it couldn't be both? eg. 3>6>7.
Thoughts and comments welcome.
Given the possibility/assumption of panspermia, spreading hydrocarbons and possibly even simple enzymes between systems, is it plausible for a habitable planet to produce complex life forms that share at least marginally metabolizable compounds with us even if they didn't develop the same DNA?
(I find it stretching the limits of plausibility that an ecosphere on a distant planet would use DNA - even if it started with mostly the same components as us. It might be similar in function to DNA but I find it hard to believe DNA is the one possible molecule that can develop complex life.)
How similar (and thus, how less plausible) would an alien ecology's chemical structure have to be to be marginally metabolizable by humans (if not wholly nutritious)? Alternately, how dependent on the DNA molecule itself are the proteins we need for nutrition?
I know we need carbs - but they're pretty simple. I know we need proteins but they're super complex and, in my opinion, very unlikely to match ours.
But what if the breakdown could be helped along? Say, a chemical additive that would break down alien proteins enough that they were usable by us?
Maybe it would only have to be for short durations i.e.a trip into the wild - as long as they got back on human food in some reasonable time-frame - or could at least supplement their diet with human food for the duration.
Assume technology and bio-chemistry is a century ahead of ours. Assume colonists have had some decades to work on the problem.2.
How difficult might it be for an alien organic critter to emit and detect radio waves? (How/why they evolve this - and the energy budget it might cost - might be another matter.)
Most Earth marine species can detect electricity, and some, such as eels and catfish, can produce it. Is it a big leap to go from electrical pulses to producing bio-chemo-electric sparks (spark-gap radio?), and then to fine-tuning them to produce primitive radio waves? Not hi-rez, like sonar, but they might be able to communicate or sense each other across some distance.
3.
How plausible is a super-Earth ocean world with a goldilocks climate but without the crushing gravity? I was hoping for a world about 1.5 times Earth, but less dense (say, 3g/cm^3), so that its gravity works out to Earth's or less. I looked up ocean worlds and it seems there is an upper limit - that of a small moon. Much larger and the barrier between vapour and liquid and solid seems to disappear. (I guess this plot detail isn't critical. I wanted a vast ocean world but it could simply be an ocean worldlet.)
4.
Can such a world hold on to its atmo? Or will it be stripped away like Mars? Ideally, a thick atmo is better. Looking to build a world where flying is easy.
5.
I'm looking at a primordially radial body plan - like jellyfish and diatoms - as opposed to bilateral. The first life might have been 3-sided, but later mutations produced 4-, 5-, 6- and 8-sided forms, creating the various phyla. Might it be more plausible for mutations to double a symmetry-axis, versus add a symmetry-axis? eg. 3>6>9 versus 3>4>5. Any reason it couldn't be both? eg. 3>6>7.
Thoughts and comments welcome.
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