[OT] Short sci-fi story: The Lifeboat

[dogscoff]

Godd stuff Geo. This story could turn into a really cool collaborative project.

[sachmo]

Great addition, Geo!

[geoschmo]

I thought it was an interesting idea you started there. Couldn't resist putting in a bit.

I am curious about one thing. Do you think the aliens warnings against eating anything not native to earth would be absolute? Seems to me that organic matter is organic matter, is it not? I'm sure there would be things that are poisinous to humans, but that's true even on earth. Perhaps someone could explore that idea a bit. Would make the prospect of a trans-continental journey within years instead of generations a bit more plausible.

[primitive]

Great stuff. Me want more

[dogscoff]

Do you think the aliens warnings against eating anything not native to earth would be absolute? Seems to me that organic matter is organic matter, is it not?

Someone stop me if my science is off here, but here's how I understand it:

Most of the things we eat are pretty complex- proteins, fats, sugars and vitamins- and they are all produced by plants or animals. For them to exist on another planet, therefore, that planet must have evolved its own plants and animals that produce those same molecules: Parallel evolution might well come up with something similar or identical to Earthly forms, but just as none of us seriously expect to find humanoid aliens with easily recognisable body parts and features, I think we're unlikely to find anything with identical or near-identical bio-chemistry.

I guess we'll never be sure until we get to another planet and find out, but I think it's likely that stuff evolved on another world would be inedible to us.

On the other hand, the bio-chemistry is almost certain to have *some* similarites: Oxygen is almost certainly going to be part of the equation, because no other element is at once stable and volatile enough to contain and then release the energies needed for life. Hydrogen is another likely contender because (A) there's bloody loads of it and (B) it comes packaged up with the oxygen in the form of water. Carbon is likely to be there as well, because not many other atoms can form themselves into such complex molecules. That gives you all the necessary ingredients for carbohydrates (edible sugars). Granted, there are probably a zillion ways those three elements could combine, but I guess it's reasonable that our survivors might find something that could be boiled down into edible carbohydrates.

Finally, there are some simple nutrients we ingest that are available in non-organic forms and therefore would be easy to find on another planet: iron, zinc, magnesium (calcium?) could probably be sourced locally- daresay you could dissolve them into drinking water, if your local friendly mountain stream hadn't already done the job for you.

Anyway, for plot purposes it's quite an interesting question. Anyone with some actual knowledge rather than my pop-science want to chip in?

[geoschmo]

My actual knowledge isn't any more then yours, but my best guess would cause me to be a little more optimistic. Our bodies don't really need specific types of plant and animal matter afterall. Our digestive system breaks those down into the basic nutrient blocks that our body does need. And those basic nutrients should be pretty much the same, despite being combined in radically different ways. Of course our survivors would probably need a chemist or botanist and some laboratory equipment to be able to determine what is safe to eat and what's not. Since we wouldn't have millions of years of common memory to rely on.

[sachmo]

But if you are desperate enough, you'll eat anything.

Day 1: "Hmmm...that purple leaf with spikes on it on this alien world doesn't look very healthy."

Day 47: "Munch. Munch. Mmmmm, purpley."

[clark]

Not very knowledgeable myself, but it would seem that there might be some things we could digest and process, and some things we couldn't. It really could go either way (think peanut allergies- they lack the enzymes to break down the peanuts)

I might mention about the story, which is really good, what the heck are the cows going to eat?

[dogscoff]

I might mention about the story, which is really good, what the heck are the cows going to eat?

Who knows... maybe nothing. John's farm is likely to have provided some vegetables and/or wheat/oats/barley type stuff. Then there was the turf brought by the Kiwis, that would be good for a bovine snack.

I think it's more likely that the people will eat the cows, unless camp two can help=-)

Originally posted by geoschmo:
My actual knowledge isn't any more then yours, but my best guess would cause me to be a little more optimistic. Our bodies don't really need specific types of plant and animal matter afterall. Our digestive system breaks those down into the basic nutrient blocks that our body does need. And those basic nutrients should be pretty much the same, despite being combined in radically different ways. Of course our survivors would probably need a chemist or botanist and some laboratory equipment to be able to determine what is safe to eat and what's not. Since we wouldn't have millions of years of common memory to rely on.

Caveat: My understanding is also based on pop-science and sci-fi, but here goes...

Our digestive systems break food down by enzyme action. It's not enough that a molecule be composed of the right number of atoms of Carbon, Oxygen and Hydrogen, they also have to be the right shape for the enzyme to be able to "fit" and catalyse a reaction. For example, it's possible to make sugars whose molecules are the mirror-image of the shape of "normal" sugars, and these manufactured sugars will pass straight through the system without being digested because our sugar enzymes don't match them.

And supposing we can digest the alien plants (or animals)? Humans digest proteins by breaking them down into their component amino acids, absorbing them into the bloodstream, and then re-assembling them into the proteins we need. But we need a particular balance of IIRC eight key amino acids, in the right proportion. It's possible for example for a badly chosen vegetarian diet to contain lots of protein, but for the protein to be nutrionally useless because key amino acids are missing or in short supply.

Given how many possible combinations of protein and polysacharride (it's a long time since I've had to spell that...) there are, it's hard NOT to image a carbon-and-water based alien bio-chemical ecosystem that's like ours, but not like ours enough to be edible (or at least, nutritious when eaten...)

Mark