I am so glad even ateroids are going organic now! Namaste.

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_/\_

There are pretty free range as well!

The fluorescence test showing racemic mixtures of the enantiomers is maybe the most significant datum - we kinda knew they had a whole bunch of hydrocarbons from distant observation spectrography, but the demonstration of an abiotic origin is a - for panspermia and a + for abiogenesis.

How can we be sure it’s of abiotic origin?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6027462/ TL;DR: Biotic implies L-chirality. Ryugu exhibits balanced chirality.

Earth biotic origin implies L, I think it is theoretically possible if life developed elsewhere that other enzymes may preference R. AFAIK our enzymes are generally conserved throughout life

Indeed. Asimov’s “Left hand of the electron” has an essay which explores and explains why life inevitably ends up with a chiral preference.

"Biotic implies L-chirality" on this planet sure, but it's one data point to extrapolate from. It's not enought.

This is the data point we discuss panspermia vs abiogenesis upon, R-chirality couldn't have spawned the L-chirality lineage here.

>left and right structures were present at approximately 1:1

> "The diversity of soluble organic molecules detected in the Ryugu samples is comparable to the diversity of organic molecules found in carbonaceous meteorites. However, the molecular distribution of low-molecular-weight organic compounds is relatively low, similar to the distribution of organic matter in carbonaceous meteorites that have been strongly affected by aqueous alteration. This is also consistent with mineralogical characteristics revealed by the initial analysis teams."

So there's a class of meteorites, carbonaceous chondrites that have up to 3% of organic matter. 5% of all meteorites belong to this class. The Hayabusa2 samples have the same level of organic matter.

Cool. A new rock. But the cooler part is that these rocks were likely exposed to water.

>> But the cooler part is that these rocks were likely exposed to water.

Water is everywhere in space. Only amongst the inner planets is it baked away by the heat of the sun. Out past Jupiter, most every rock seems to have substantial water content. Most of that is ice, but any source of heat turns that into water for a time. Two asteroids colliding would produce some liquid water in their interiors, long enough for some organic chemistry to happen.

Umm, I don't know but would guess water-ice sublimes over time in a vacuum.

The rings of Saturn are almost entirely little chunks of water ice, and they are stable over many hundreds of millions of years. Cold ice (below about 150K) has a very low vapor pressure.

Sublimates in one place, condenses in another. It moves from sunny parts of a body to darker parts. And since everything is rotating, the net effect is minimal.

For that to happen, it can't be gravity that keeps a single molecule near long enough for that to happen - dipole forces at a fairly large distance in vacuum over enough time... maybe... at enough distance from the sun. Maybe. Maybe.

Static electrical field from the asteroid, stoked by the sun?

Related reading: the Murchison meteorite.

https://en.wikipedia.org/wiki/Murchison_meteorite

It’s an extensively researched meteorite that is just full of organic molecules.

Thought experiment, anyone wonder what would happen if we started space mining, and all of a sudden we started finding fossils in asteroids? Like they're bits from ancient worlds that had life on them? Perhaps feasible in a universe just 15 billion years old, that things recycle and get moved around, and on a long enough time scale parts of earth could be asteroids in a far off galaxy, that isn't the milky way, long after our sun supernova's.

Best episode of Time Team ever

I have a feeling that our asteroid belt is littered with dead, dying, or sleeping Von Neumann probes that have been sent out by all the civilizations who came before us in the Universe.

I think that space mining is a very important endeavour that we should start to undertake as soon as possible.

> As a result, 15 types of amino acids were detected, including proteinogenic amino acids such as α-alanine, glycine, and valine, which are common molecules in terrestrial life, and non-proteinogenic amino acids such as β-alanine, aminobutyric acid, and isovaline. The detected optical isomers (Note 5) were racemic, existing almost 1:1 ratios (Figure 4). ...

The 1:1 ratio of optical isomers is not consistent with life as we know it, suggesting an abiotic origin for the amino acids.

Amino acids are actually not very hard to make from simpler components. But quite harder to make enantiopure.

What's really hard to do is turn Acs into anything approaching the complexity we find in abundance in living systems.

It's enlightening to consider what evidence would be necessary to support a claim for the past or present presence of life. Clearly amino acids by themselves are not enough. And even enantiomerically enriched AA's could arise abiotically.

What you might look for is molecular complexity. One of the pioneers in the field, Leroy Cronin, developed a theoretical framework (Assembly Theory) that could be put into observational practice.

https://en.wikipedia.org/wiki/Assembly_theory

Cronin makes the analogy that if you found anything as complex as an iPhone on Mars, that would be pretty good evidence of the presence or at least influence of life at some point. It turns out you can do that at the molecular scale, but you need to come up with a way to define "complex."

For me, the ready abundance of AAs is plenty. If we saw a paucity of AAs outside earth then we could say we have evidence for the stuff for life being possibly unique to earth. That its presence seems to follow a knowable, significant rate suggests quite a lot of opportunities.