There was a science fiction story that came to mind, but I don’t remember what it was called. In it, a human is taken by human invaders. ISTR that the aliens were not mistreating him, and he may have been destined for a zoo. I could be wrong about that.
In any case, the human was either allowed to care for an animal, or else he was summoned to try to help a sick animal. He held the animal and caressed it, and somehow tricked the aliens into petting a live rattlesnake. The snake bit the handler(s) and they either became very sick or they died.
So here’s the question: I’ve heard that aliens would be so different from us genetically, that Earth germs would not harm them. Would they be harmed by a snake’s neurotoxin or hemotoxin?
If the alien life forms are carbon-based (and they almost surely would be) then it is very likely that they will use proteins as important structural and biochemical components. Since many snake venoms contain proteolytic components, it’s quite possible that they would disrupt the alien’s tissues enough to cause death.
Other physiological elements may be more specific to Earth life. However, it is possible alien life forms might use ATP, and use some kind of sodium-potassium conduction system for sending nerve signals and muscle control. If so, there are components in some snake venoms that could affect these processes.
Earth germs would be less likely to affect aliens because they often depend on hijacking some rather specific genetic or physiological processes, which would probably not be the same in aliens. Snake venom has components with a more general action.
Not to hijack my own thread, but I’ve heard that the venom of the Australian funnel web spider is dangerous to humans because of an accident of evolution, and that the venom doesn’t affect other (non-prey) animals. Is this true?
The story you’re recalling is called Knock, I believe.
as to whether venoms and poisons would affect an alien - I believe it’s impossible to say - even if the alien had body chemistry that was broadly similar to ours (carbonm hydrogen, oxygen, sugars, proteins etc) a neurotoxin might do nothing if the alien’s body transmits sense and control signals in a different way or even in the same way, but using different ions enzymes and proteins
corrosive or enzyme-based digestive poisons might be expected to be more general in their range of victims.
on the other hand, a good many substances benign to us might be lethal to aliens - although it seems unlikely that water would be one of these
It’s impossible to say of course, but the odds are pretty slim. Snake venom tends to be either digestive enzymes or molecules that specifically interfere with physiological systems. The odds of any alien having a similar enough physiology is remote. The effect of being envenomated by an alien organism would probably be something akin to a bee sting, a localised reaction to foreign material and little more.
The only major biological product that is likely to be widespread is across all lifeforms is fat. Carboxylic acids are so simple that they occur even without the presence of life, so they would almost certainly be produced by all lifeforms. And long-chain carboxylic acids have so many useful properties that it seems almost certain that all life-forms would make use of them to some extent. So if your venom contained some sort of lipase it would be reasonable for it to cause problems for most lifeforms.
This reminds me of a short story I wrote in high school. It annoyed my English teacher to no end, but my chemistry teacher loved it.
In the story, people discover an Earth-like planet just as political tensions are boiling. A small group throw together a spaceship and barely escape the nuclear holocaust with minimal supplies. When they arrive, they discover that everything on the alien planet has the wrong chirality and they all starve to death in the middle of a lush forest.
What you’re really asking is “what is the biochemistry of alien life?” The answer, of course, is that we don’t know. We can speculate and make informed guesses - personally, I think it’s astronomically unlikely that any alien life would be similar enough to our own to have any kind of common reactions like this - but until we get at least one data point, it’s nothing but speculation and guesswork. As always in science, the most carefully crafted, beautiful pile of logic and deduction can be completely destroyed by one observation that’s inconsistent with your theory.
That explains a study I read about where they kept giving this cat massive doses of funnel-web poison, and the cat just sat there taking it, and was perfectly fine. And then it got adopted and lived out its life as a pampered house cat.
What makes you say this? I’ve always wondered that… just because the only life we know if is carbon-based, why wouldn’t an alien be, say, silicon-based… or even based on elements we haven’t even discovered?
Because no other element is capable of forming the extremely complex molecules that carbon can because of its ability to form four bonds. Silicon can also form four bonds, so it is sometimes proposed as an alternative basis for life, but it doesn’t have anywhere near the versatility that carbon does.
We have discovered all stable, non-radioactive elements. The only elements yet to be discovered are very high atomic weight and highly unstable (radioactive).
Funnily enough, scientists postulate that there’s an “island of stability” among particularly high-weight elements; that many of the high-atomic-number stuff that scientists make is very short-lived, but as you get particularly high, things become more stable. There’s some evidence for this; they’ve just recently synthesized element 117, and it’s more stable than 116.
http://www.nytimes.com/2010/04/07/science/07element.html?ref=science
ETA: I don’t mean this to dispute your conclusion that life will probably be carbon-based, with a very low possibility for silicon-based. Rather, I’m nitpicking just this tiny detail, in true SDMB “Got Cite?” tradition.
It’s just basic physics. Elements are defined on the basis of how many protons their nuclei contain (atomic number). We have identified all elements with atomic numbers of 118 or below. No elements with atomic numbers above 94 (plutonium) occur naturally; they are unstable and radioactive and produced synthetically. They could not possibly form the basis for life.
See the Periodic Table, which includes all known elements.
“Stability” of course is relative. These very high-weight elements are speculated to have half-lives in days or perhaps years (rather than in fractions of a second), but that’s still far too short to base a life-form on, which is the question at hand. (Imagine an organism which had half of its atoms disintegrate in a year.) And of course these elements are all artificial.
Because what makes an element and element is the number of protons in the nucleus of the element. And we’ve discovered element number one–hydrogen, number two–helium, number three–lithium, number four–beryllium, number five–boron, number six–carbon, number seven–nitrogen, number eight–oxygen, and so on and so on, up through the periodic table.
And when you get to the elements heavier than uranium (number 92) you find that they are all highly radioactive and break down into other elements very quickly. Some are so radioactive that atoms of the element tend to last much less than a second before being destroyed.
If there were higher number elements that were stable enough to last for a long time (like millions of years), then the obvious question is, where are they, and why can’t we find any of them? The theorized island of stability is only relative stability–we’re still talking about microseconds of existence.
And siloxide chains have shorter and stronger bonds that aren’t as amenible to the conformal variations that allow the construction of complex reactive proteins. Silica-based “organic” biochemisty would require more aggressive solvents and higher energies than carbon chains, and probably wouldn’t allow macromolecules of sufficient complexity. Carbon-silicon bonds are possible (although apparently absent in terrestrial life) put pure silicon polymer biochemistry appears unlikely.
Life based on transuranic elements is grossly unlikely for the obvious reasons that such elements are rare, unstable, and have electrochemical properties which are not well suited to stable chemical bonds at in the useful range of bond energies.
I don’t mean to contest your claim that life can’t be based on these trans-uranics; we haven’t seen any of them naturally in the universe, so they’re either they’re impossible to produce naturally, so life can’t form based on them, or they’re unstable, so life can’t remain based on them. I am curious at your point that they’re “speculated to have half-lives in days or perhaps years,”- do you have a cite for that one? I haven’t seen anything about this other than that an “island of stability” probably exists.
