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Comment by JPLeRouzic | Hacker News Reader

They didn't detect RNA which would be extraordinary. What they detected is Uracil, one of the molecules that is found in RNA.

They didn't found any other nucleotides.

"Other DNA/RNA nucleobases were not positively identified in both the A0106 and C0107 samples. This does not necessarily exclude a possibility that those nucleobases are present in the Ryugu samples, but just they may be below the detection limit under the experimental conditions employed"

https://www.nature.com/articles/s41467-023-36904-3

For having RNA you need a molecule composed of roughly 200 nucleotides. If we find RNA, it would be very indicative of DNA, so of living beings very similar to us

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not even a nucleotide- just a nucleobase. It's missing the ribose sugar so it can't form polymers.

> if we find RNA, it would be very indicative of DNA

Or evidence for the RNA world hypothesis [1].

[1] https://en.m.wikipedia.org/wiki/RNA_world

> For having RNA you need a molecule composed of roughly 200 nucleotides.

miRNA are order of magnitude smaller.

That's after DICER/Drosha processes the pre-miRNA/pri-miRNA transcripts. The pre-miRNA/pri-miRNAs transcripts can be a magnitude equal to or greater than 200 nts.

If it had 200 nucleotides you'd know for sure it's a contamination. RNA isn't very stable (in our conditions, I have no idea how it does at 3 Kelvin, blasted with radiation for a million years...)

RNA can be stable if it's dry but DNA is much more stable. I can't see DNA surviving undamaged on the surface of an asteroid, but I could see: DNA getting somehow embedded in a rock agglomerate, then the rock gets ejected from a planet, lands on another planet whole, and then the rock breaks and now you have dna on another planet. With enough deep time, this could occur (possibly) but I can't see it as an effective method.

instead, better to take tardigrades, induce tun state, embed that in rock, and let that float around for a while. They have pretty much everything needed to survive including safe storage for DNA, DNA repair enzymes, redundant DNA, radiation-resistant exterior, etc.

> They didn't detect RNA which would be extraordinary.

Correct, and they don't say that. They found an RNA compound. Uracil, one of the molecules that is found in RNA.

Not sure of the purpose of this comment to regurgitate what's found in the article itself, which goes into greater detail.

As someone who reads the comments more than the articles, I always appreciate when this kind of clarification is in the comments. It's one of the best parts of HN.

I appreciate it too

Honestly, me too, to the point where I open the comments in tabs before visiting the articles. It may be biased, but seeing what the HN hivemind has to say about the topic is usually as valuable, and often more valuable, than the linked article itself.

There are also situations like this one where, while I find the headline interesting, I don't care enough to read through the whole link - so I'll check the comments for any significant additions or corrections or clarifications, and sometimes read the interesting discussions that occur, but won't even click through to the main link.

It might come down to a question of number of perspectives - the linked article is usually by a single person/group (or worse, a news org poorly interpreting the results of a group), while the HN comment section will be filled with a variety of people, often with domain specific knowledge and experience.

All that to say, HN is an interesting community, and I don't think there's a "wrong" way to interact with/be part of it (as long as you're being respectful etc.).

The point is that the headline is ambiguous.

RNA is a compound, and Uracil is also a compound. Thus you cannot tell from just the words "RNA compound" whether they mean a compound that is RNA or a compound that is part of RNA.

Most of us are laymen to the subject. Please people, feel free to continue regurgitating concise and understandable information.

Fittingly enough, mother birds regurgitate their otherwise indigestible food so that their young can digest it.

Yeah, even the title here (now) is "RNA compound" not RNA.

It was when I posted my comment.

I would guess that whatever organic molecule was on that asteroid, it died off from the intense radiation in space.

Organic doesn't necessarily imply living.

It actually does: "Organic: relating to or derived from living matter"

This is the difference between standard usage and jargon.

Chemists consider any covalent compound involving carbon that isn't only carbon to be "organic".

Normal usage is what you wrote.

Alternative but widespread usage is "agricultural products made without synthesized fertilizers and pesticides".

Oh, and business jargon uses organic to mean "natural market growth or internally developed capabilities", as opposed to buying the growth or capability.

And in military usage, organic means "a permanently assigned assisting unit", so that routine vehicle maintenance, for example, is handled by people who travel with the vehicle.

It's like astronomer talking about metals. By which they mean everything that's not hydrogen or helium.

To their credit, I remember something about basically every element ionizes to some extent in space, thus exhibiting the "sea of electrons" behavior characteristic of metals.

> like astronomer talking about metals

This is particular to stellar astrophysics. Astronomers studying asteroids maintain the conventional definition.

I've taken to using "organic-branded" for the agricultural products, since "organic" is essentially an FDA brand, with regulations for usage of the branding. Its also my personal rebellion against "organic" having a functional meaning of "magicalhealthygoodness" in some circles.

Yes, /originally/ 'Organic' meant from living matter. However, when it was discovered that urea could be synthesised in the lab, we realised that there was no real distinction between 'living' molecules and 'dead' ones ...

Nowadays, 'organic' refers to chemicals with a majority (?) carbon content. It gets a little tricky for things like diamond and graphene (both materials) or for compounds that have a lot of heteroatoms.

Oddly enough, another nucleotide base (adenine) is exactly 50:50 C:N and has been proved to be synthesised from just HCN. So is it 'half'organic' :)

As a (former) organic chemist, this is spot-on. "Organic" doesn't really have a strict definition, but it's not so much "majority carbon" as it is presence of a C-H and/or C-C bond. I personally don't consider diamond and graphite organic, but some do. Carbon disulfide and phosgene (COCl2) usually aren't regarded as organic. And as you mentioned, stuff with carbon and lots of carbon atoms is a grey area (looking at you, azidoazide azide, but not looking at it too hard, it might not like that).

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

Organic compound simply means that there are carbon-hydrogen bonds or carbon-carbon bonds in a compound.

The view that this requires "life" was a legitimate theory back in 1800s and was disproved in the late 1820s. (See the wiki link for more details)

What kind of intense radiation is needed to kill a molecule of teflon?

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