What is the mystery? Perhaps one handedness was just first by chance and won because it self replicated the other handedness away by consuming it as food.

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griffzhowl 7 months ago | parent | next [-]

Well, that's the question isn't it? Is it just a frozen accident, or is there some nonarbitrary reason for the left-handed molecules to be favoured?

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throwawaymaths 7 months ago | parent | next [-]

Sure but that might be an unknowable problem. What if the difference in likelihood were 60/40.

You could go down all sorts of rabbit holes and none of them would truly be falsifiable unless you observed an enantiomeric lifeform on some distant planet.

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madaxe_again 7 months ago | parent | prev [-]

Perhaps aliens eat right handed life, but left handed life is poison to them.

Seriously. It would be a pretty good selector, and said “alien” need be no more than a snippet of RNA - and it would be entirely gone from earth now, eliminated by us sinister life forms.

The only evidence would be the ubiquitous absence of R-entantiomers in life.

I think I might be lifting from Asimov - The Left Hand of the Electron.

	▲	Terr_ 7 months ago \| parent [-]
		That kinda kicks the can down the road though, because we are faced with almost the same set of questions except about the hypothetical alien life.

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throwawaymaths 7 months ago | parent | prev | next [-]

(Comsuming enantiomers and pooping out metabolic fragments in its native chirality)

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alganet 7 months ago | parent | prev [-]

That assumption is even more mysterious.

Why one specific handedness "won"? What caused the other one to be food? How can we be sure it was by chance?

Lots of questions.

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throwawaymaths 7 months ago | parent [-]

> Why one specific handedness "won"?

Place two competitors at the origin on the number line. On any given turn they walk either to the left or to the right, with exactly 50% odds of each. First competitor to +100 wins.

> What caused the other one to be food?

Basic chemistry.

> How can we be sure it was by chance?

We can't. If the odds are sufficiently close, we probably can't be sure it wasn't chance, either. If we go to space and find a planet with life with the other handedness, it was probably chance.

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alganet 7 months ago | parent [-]

I have so many questions.

How do you know the evolutionary model of these early organisms? How do you know that a competition had taken place?

If you can't know if it is by chance of not, why hypothesize it?

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throwawaymaths 7 months ago | parent [-]

Well we don't truly know. A full analysis of the best prebiotic chemistry hypotheses can't fit in an HN thread so if you want your questions answered you should consider studying organic chemistry, biochemistry, and then going to chemistry grad school.

Suffice it to say all of the best models are reasonably plausible, and like everything in chemistry operates on the principle of chance molecular motions.

	▲	alganet 7 months ago \| parent [-]
		You said there was no mystery. I was under the impression that you knew and had a very simple explanation that could be referenced to. When I think of "chance molecular motions", I don't immediatelly jump to "well, that leads to biological evolution". I don't understand how you connected the two ideas. I mean, there's a path there, but a whole theory is missing. I searched for it but couldn't find it. I really don't know organic chemistry, but I'm fascinated by the mystery. You don't need to write here, just give me some good links or references I can read that support your case.