It's my understanding that the RNA world hypothesis is pretty much widely accepted these days anyway. The open question is more how you get to the RNA world in the first place. The RNA hypothesis as such is more an hypothesis of what preceded life based on DNA and protein, and less so a theory of the origin of life from non-life per se.
The two main camps today seem to be "metabolism first" with people like Nick Lane and "genetics first" with people like Jack Szostack.
I used to favour the genetics side but I've been leaning more towards metabolism recently. Lane's research on this has been fascinating.
As for a good introduction to what his(and the many other people working in his lab) research is getting at, I really recommend the podcast episode he did on Sean Carroll's Mindscape podcast.
RNA is a structure capable of being both a store of data and a catalyst.
As RNA forms spontaneously with time, eventually you would end up with an RNA which can catalyse its own ingredients and replicate. As soon as you have one, it would replicate and take over the pool. Random changes would then lead to advancement.
Membranes also form spontaneously so the replicating RNA could find itself a bubble through random chance and live in it.
Where do you think vitamins come from ? Haven't you seen Star Wars ? (Millenium falcon lands inside an asteroid and the heroes are almost eaten by a space "dinosaur" living inside the asteroid) /s
This has gotta add weight to the Panspermia hypothesis.
Panspermia is a hypothesis that suggests life on Earth may have originated from microorganisms or organic matter that traveled through space, potentially from other planets or moons in our solar system or even from other star systems.
If the creation (natural synthesis) of an organic molecule requires extraordinary conditions (some cosmic very rare & special place), AND, such stupendously rare precursors are catalysts of generation of more complex organic molecules (like RNA) in more common conditions (rare but equally distributed planets like Earth), then an ancient chance event somewhere out there is possibly the source of all potential DNA based life-forms via astroid seeding. The entire issue with DNA/RNA is how did these complex molecules naturally arise.
The opposite. If such compounds are common in asteroids absent life, then the rise of RNA/DNA on different planets is more likely to be happening spontaneously, without anything traveling between planets. This finding suggests that some building blocks of life may be very common, increasing the chances of life arising locally without need of panspermia.
Its isn't evidence against, but it is evidence that panspermia is less necessary than previously thought. Should we detect life out there somewhere, the fact that these compounds are more universal decreased the likelihood that that detected life is related to us through panspermia. The fact that life in two places uses RNA no longer means that it must be directly related to the RNA/DNA-based life on earth.
The opposite would be Earth was hit by other objects in the distant past, and the collision blew large chunks of Earth into space. Complete with B3 and RNA. (Especially credible as the body in question is a near Earth asteroid.)
All the posited explanations are reasonable hypotheses in my opinion.
Rather, IMHO, it gives us more information on how the conditions on Earth might have been when life emerged. We're getting more and more clues that a lot of the basic blocks of life are present in asteroids and thus might have been present on the primordial Earth as well in some watery soup where life emerged.
Not quite. Panspermia says that life exists on other planets and then somehow is distributed through space to other planets. The OP was just saying that the "building blocks" exist throughout space but life develops on planets.
That’s a cope, not an explanation. It’s like saying “God made the world”. It doesn’t answer the question because then the question is who made God.
If your theory relies on external creation on another planet or whatever, then it’s meaningless because how did life start there. If life could start there then it could have started here so why do we need your theory at all?
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"
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
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.
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.
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.
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).
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.
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.).
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.
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.
>“Since the Hayabusa2 spacecraft collected two samples directly from asteroid Ryugu and delivered them to Earth in sealed capsules, contamination can be ruled out.”
I seriously doubt that it could be "ruled out" just like that.
For one, the spacecraft (or the empty capsules) could have been pre-contaminated before their launch.
Second, the capsules could have been contaminated after arrival even if they were "sealed" (perhaps the seal had issues, or maybe it happened when they opened them, since one assumes they couldn't test still sealed capsules, they'd have to open them).
I wonder if there's a "control group": a tiny but identical container that goes through all the same steps. Nothing can ever be proof that it wasn't contaminated or a seal was broken on the real but not the control container, like, nothing will convince an Internet conspiracy theorist, but a control vessel and a handful such missions ought to prove beyond reasonable doubt that it wasn't contaminated from earth. I'm personally already willing to trust that they thought of (and controlled for) these things and more, since it's their job and we're just thinking out loud here.
I don't know how they do it but I always thought the best way would be to have the probe place them in glass ampules and seal them while still in space.
>You better alert the scientists that they missed something, then! That's some serious business, they must be alerted to their failings immediately!
Yes, unimaginable that scientists could have made a mistake that a layman could spot, or just said something to create good PR to their mission, even when it's inaccurate.
They also never unwittingly or intentionally BS in their research papers, right? And only a colleague (or a higher level intellect than theirs) could spot a mistake... /s
>Seriously though, do you really think these scientists are making claims, being widely reported, without having made the same conclusions and analysed the situation with all the data, not just that reported through a story on the Internet .. ?
Seriously, similar blunders have happened time and again.
In 1996, scientists at NASA declared that a 6.3-ounce
rock, broken off from a Mars meteorite discovered in
Antarctica in 1984, contained flecks of chemical compounds
— polycyclic aromatic hydrocarbons, magnetite, and iron
sulfide — that suggested the existence of bacteria on the
Red Planet 3.6 billion years ago. "August 7, 1996, could
go down as one of the most important dates in human
history," intoned one newspaper report. But within two
years the theory began to crack.
Traces of amino acids found in the rock, crucial to life,
were also found in the surrounding Antarctic ice. More
damning, other non-Martian rocks — rocks from the moon,
where it is clear life does not exist — showed the same
"evidence" of life. By November 1998 an article in Science
declared "most researchers agree that the case for life on
Mars is shakier than ever."
>Because it seems you're smarter than rocket scientists. Are you a brain surgeon, then?
This particular case aside, you appear to believe that you need to be smarter than X person to be able to spot an error they made. It doesn't take a very high IQ however to see the error in the above idea.
In any case, based on the insults, did you just wanted to lash out on someone to feel better for yourself?
if you want people to engage with you seriously, perhaps avoid such a condescending tone. ditching the sarcastic italics could be a good place to start
the way it currently reads is less like curiosity and more like “how dare you question the judgment of scientists”, as if questioning results isn’t the absolute bedrock of science in the first place
Nowadays, to a lot of folks, questioning isn’t the bedrock of science. “Trusting the experts/science” is. That’s the root behind a lot of issues we’ve seen socially, especially over the last few years.
Disagree. It's trivial to question. It's non-trivial to do the work required to show evidence for or against some proposition. What is at "the root behind a lot of issues we've seen socially" is the easy path of questioning something without actually being able to do the work required to back up one's claims or counterclaims. So I believe the reaction which you think of as "trust the experts / science" is actually "do the work and show the evidence".
If a paper is published which claims that such-and-such drug shows effectiveness against shingles, it's easy and trivial to say, "Not so fast my friend" followed by any number of statements about Big Pharma, citing previous situations in which a claim was later shown to be false, etc. But while all of those things may, in fact, be true, they don't bring to bear any actual evidence that this particular drug study is flawed and exactly how.
It's also trivial to accept though. And in a world where you can't (for time and effort constrains) check every announcement personally, and where expert proclamations aren't always correct so thay you can just take them as granted, there are still reasons to have an estimation (as a layman but even as a scientist) of something being true or not summarily.
The alternative I've suggested is rather different than the suggested alternatives of accepting results or taking them for granted. In another comment I said:
> I'd suggest reading every paper critically, realizing (as most people do) that the results are tentative, and either letting it go at that, or dig in and do the hard work to figure out what may be flawed in the work presented. Then work with the authors or publish a paper of one's own pointing out the flaw and the new resulting analysis.
I think the problem here isn’t the specifics, but the borderline-nasty beration of the commenter simply for questioning the result
yes, I agree, it would be better if they had a specific criticism of the methodology, but an appropriate response is simply to ask for such a thing, not to jump on them for questioning it at all, which is what happened here. do you see what I mean?
what happened:
>I think there could be contamination of the samples
>oh wow how adorable, what’s next from your big book of ideas, little one?
what would have been healthy:
>I think there could be contamination of the samples
>interesting. do you have a specific criticism of their methodology?
I know better than scientists have time and again made mistakes, and claimed something with certainty, even though it was wrong, despite, you know "actually working with the data and not just reading about it on the Internet".
I also know that scientists have a bias to show impressive results, and that even NASA among others, in a similar case was all too fast to jump to conclusions and make a whole show about their 'findings' and annoucements to the press, and they still got it comically wrong, despite "actually working with the data and not just reading about it on the Internet.".
Finally, I know that "we found RNA building blocks and B3" on a meteorite is less likely that contamination, so the story seems fishy and premature.
Sorry that somebody even doubted than an announcement or a paper can ever be likely wrong without being on the team who wrote it.
> Finally, I know that "we found RNA building blocks and B3" on a meteorite is less likely that contamination, so the story seems fishy and premature.
Since you rightly encourage everyone to question claims, I question this claim. How do you know this, specifically?
In other words, we have a situation where a team has done a bunch of experiments, data collection, and analysis, and then published a paper claiming "we found RNA building blocks and B3", right? And now your claim is "no, you're wrong about that," but without any experiments, data collection, and analysis. So if you're going to make a claim, provide the details, data, and evidence that substantiates your claim.
You can call it a prior (like in Bayesian probability) on the probability of such an announcement being right.
Same, to give an obvious extreme example, as I'd be sceptical about an annoucencement that "We found the perpetual machine, there was a major flaw in thermodynamics laws, here are our numbers and results", even if they're world reknown experts in physics saying it, and I don't have access to their data, or to the machine to try it myself - hell, even if I can't understand their formulas.
One would still have a prior in this case, based on a general understanding of the the world, and the possibility range where this falls.
You might have a more informed prior because you took more concrete information into account than mere experience of other such announcements being repeatedly proven wrong, the probability of RNA being found on a meteor sample, the probability of the team just being lax with their annoucement to get publicity and grants, and so on.
Or, I guess, you think that we should never do that, and we should either do the research ourselves, or wait until someone else does, and at any point, whatever they say as their conclusion, them being experts and having done the work and everything, should be the final word.
Which probably means that as you see it, it makes no sense, to have a belief on anything or its refutation as likely or unlikely, unless one has either replicated the study and checked the conclusions, or found specific actionable faults.
It's fine and quite legitimate to have a prior, as your example of a perpetual motion machine illustrates. Along with the prior it's also important to understand how typical cognitive biases can affect those priors. For example, you cite the "mere experience of other such announcements being repeatedly proven wrong" and "the probability of the team just being lax with their annoucement to get publicity and grants." These might be examples of availability bias. Clearly these things happen. The question is whether they actually happen with a frequency that would justify the statement:
> Finally, I know that "we found RNA building blocks and B3" on a meteorite is less likely that contamination, so the story seems fishy and premature.
Regardless of each of our own priors and biases, respectfully, you don't know this. You don't have evidence that shifts the probability in this direction. Or rather, you haven't presented any. You haven't pointed out a specific flaw in the experimental design, instrument design and operation, data collection and analysis. What you have done is state your strong prior suspicion that something is wrong. That's not knowledge, and it's nothing that anyone else could base their assessment upon. The statement is simply a statement of your prior, nothing else. It's not a material statement about the actual paper, its data, analysis, or its conclusion.
Actually its your tone-policing that is so disruptive to the conversation - you seem to have issues with peoples' statements given confidently - but fortunately there have been many more responses to your rash argumentation than I care to give.
I think what the other poster is trying to say is something like the following:
There was a team / teams who planned the mission, designed and built the spacecraft and its systems & instruments, designed and performed tests on the samples, analyzed the data, and published a paper with some claims. The paper outlines their methods, test results, data, and conclusions.
Now, is it okay to question anything in the paper? Yes, absolutely.
How probable is it that something in the paper is wrong or could be improved? Definitely non-zero, it happens a lot. People who understand various aspects of the instruments used, the tests, data analysis, etc, often find some minor or major flaw in scientific papers. Could it happen with this one? Yes, absolutely.
How probable is it that someone on HN--knowing that there are lots of people on HN with diverse expertise--will find something wrong with the paper, and that the substance of the flaw they found is:
> I seriously doubt that it could be "ruled out" just like that.
> For one, the spacecraft (or the empty capsules) could have been pre-contaminated before their launch.
> Second, the capsules could have been contaminated after arrival even if they were "sealed" (perhaps the seal had issues, or maybe it happened when they opened them, since one assumes they couldn't test still sealed capsules, they'd have to open them).
Non-zero, but very low. Could it happen? Yes, it could very well be that the team(s) involved did not consider that contamination could occur before or after the sample was obtained and analyzed. How likely is it? Hard to say, but if it happened, the critique would not take the form of "Hey, it could have been contaminated!" Rather, it would take the form of "I notice in the sample handling procedure that such-and-such technique was applied. Further, in the data analysis, such-and-such test was not done, therefore one could not rule out ..."
My claim wasn't that "the team(s) involved did not consider that contamination could occur before or after the sample was obtained and analyzed".
I merely gave a trivial (even exhaustive!) enumeration of possible contamination cases that could still have happened (regardless of whether they are targeted against in their protocols), not some novel avenue for contamination that I claim to be "smarter than the scientists" to come up with.
Of course they knew of those contamination possibilities. I didn't say anything about them having missed such basic contamination cases.
What I did (and am) suggesting is that they probably are too confident in their protocols having been executed correctly and being 100% tight with no possibility of error. And that that those avenues of contamination are still a real possibility (protocols to prevent them be damned).
Now, this might not be the case. This might indeed be space travelling RNA-combound and B3 vitamin.
But I'd say that the probability of contamination being the case and someone (on HN or wherever) calling it correctly, is equal to the probability of the samples being contaminated. Which is not that small.
Spotting some novel contamination route they haven't thought off would indeed be very rare and a major feat. But merely been less confident (that they are) in their thoroughness and in their preclusion of contamination, is much easier to claim and be correct while doing so.
> But merely been less confident (that they are) in their thoroughness and in their preclusion of contamination, is much easier to claim and be correct while doing so.
But it's a trivial observation, and one that isn't actionable or testable. For the team to have designed and performed the instruments, experiments, data collection, and analysis to say "We're confident in our results and we have ruled out contamination" is substantive and is backed by data and actual experiments. For someone else to say, "I'm not so sure, I think it could have been contaminated," and then provide no actual argument or data on what could have gone wrong, is probably not a novel observation or comment. In addition, it's an easy thing to say (as you correctly point out) without putting oneself on the hook to show how or why.
Here's what I mean: we can confidently say about every paper ever published that "I'm not so sure." Here are the possible outcomes: (a) the paper stands the test of time, the result holds, and nobody remembers anyone who said "I'm not so sure," or (b) someone finds a flaw in the paper, works with the authors and they publish a retraction or revised paper, and then whoever said "I'm not so sure," can easily (as you say) point out how "they called it," all without doing any actual work.
I'd suggest reading every paper critically, realizing (as most people do) that the results are tentative, and either letting it go at that, or dig in and do the hard work to figure out what may be flawed in the work presented. Then work with the authors or publish a paper of one's own pointing out the flaw and the new resulting analysis.
>But it's a trivial observation, and one that isn't actionable or testable
Yes. But if they make a bold claim that "contamination can be ruled out", it's worth it to say to folks ready to take them for their word that, "it's still a possibility", even if it's not a testable finding but a suggestion.
Sure 'we can confidently say about every paper ever published that "I'm not so sure."'. But that doesn't mean we do say it for every paper ever published, or that we say it with equal weight.
The alternative is taking every research announcement at its word, and acting like it's true until it's taken down by another paper. And even then, why'd we trust the second paper refuting the first got it right?
In the end, it amounts to "if you didn't do the work or the review yourself, and din't find any specific actionable issue with it, then you should have no opinion about the probability of it being true or not".
Which is quite problematic. In the end, we often need and should be able to make a summary assessment of the possibility of a paper's conclusions being right or not (as based on our layman experience), even without working with the data, going through it with a fine comb or trying to replicate it, but based on a sense of probability of the conclusion, our knowledge of past assurances in similar statements being ultimately proven wrong, potential conflicts of interest, and so on.
> then you should have no opinion about the probability of it being true or not
Rather, I said when we read papers we should realize that results are tentative. It's fine to have some personal assessment of the probability, but it's not actionable by anyone, and communicating it doesn't assist in improving our collective assessment of what is going on in the world. I'd also suggest that we probably don't, in fact, "often need and should be able to make a summary assessment..."
Reading this comment I couldn't help but remember the research showing extremophiles replacing phosphorous with arsenic in their DNA backbone. NASA held a big press conference and made a huge deal out of its potential implications for extraterrestrial life. It was later found that the data was inherently flawed(possibly even doctored? My memory fails me) due to arsenic contamination of samples. Retracted.
Things like this do happen, and more frequently than one might expect.
Nonetheless, the goal post to pass is the scientific process and journal article review. It’s not “someone made a mistake in a study once before so all science is ruled out” as this would tend toward. We’re not doing ourselves any good carrying around old bad behavior.
If you read my comment as implying all science is ruled out due to one example, that's very much a you problem. I said or implied no such thing.
I also didn't take a stance on this research. I've yet to read the paper, and I don't read "science journalism" like TFA. But it's not like the findings are earth shattering given previous research. Therefore I lean towards optimism.
I am simply saying that scepticism is warranted even if a paper is peer-reviewed and published in Nature. The "scientific process" doesn't magically end at peer review. The process goes on, and it pretty much never ends.
If your post was simply to say, "This paper could have flaws and its conclusions could be incorrect," then yes, almost all of us will agree with you. I'm not sure it's big news, however. I would guess most of us understand that scientific findings are contingent on future experiments and results.
If your post was to point out a specific flaw, e.g., that the sample could have been pre- or post-contaminated, then it falls short of anything substantive and actionable. Nobody can do anything with it. Yes, you are correct. But no, there is not anything anyone can do with the critique. If you're going to point out a flaw, it needs to be something that you, the authors, or other PIs can check, perform, etc.
My post was clearly not pointing out flaws in this specific research. Not sure how you get that impression.
I first replied to a comment implying that just because research is widely publicised it should be accepted at face value, with a counterexample. That was all.
Then someone replied to that with the absurd implication I was somehow trying to denounce all of science based on that one example. I corrected them.
The only thing I said about this specific research was the following:
>>But it's not like the findings are earth shattering given previous research. Therefore I lean towards optimism.
If you inferred any other comment on the research than that, the source of that is your imagination, not anything I wrote.
> If your post was simply to say, "This paper could have flaws and its conclusions could be incorrect," then yes, almost all of us will agree with you. I'm not sure it's big news, however.
>But no, there is not anything anyone can do with the critique
Critique doesn't just exist to be actionable.
It can also exist (as in this case) to remind of a possibility. Especially in this case, where the possibility is precluded.
In fact that was the very intended. Pre/post contamination could still have happened, we can't just exclude it because "protocols were followed". Protocols have been followed in other cases where errors got in the way to.
Perhaps you didn't wanted to see a general comment, but somebody spotting a specific error in a specific step of the actual process?
As I said in another comment, you may be reading too much into the statement to the press as opposed to the actual paper. It's more likely that the author quoted as saying that something could be "ruled out" meant, more precisely, that the possibility of contamination is very small, but non-zero, and that the overwhelmingly more likely conclusion is the existence of said compounds.
It's worth noting that there are plenty of rocket scientists and brain surgeons on HN, although I don't know the professional background of the commenter to whom you're replying.
Well played. I do find HN to be full of "expert" commentators on any subject matter even if they aren't ;) Remember David Levinson (Jeff Goldblum in Independence Day) figured out how to defeat the alien invaders by uploading a virus to the alien ship. He used MacOS 8! Wasn't it a modem parity issue (8N1) or some other such nonsense for a space-traveling, gravity-defying spaceship?
It’s pretty clear if you read the paper they are not confident they did their job perfectly, and have erected guard rails around everything to cap the maximal contamination and established tests for assessing the extent of contamination exploiting assuming there is going to be contamination.
It would be a little weird for it to be contaminated with only uracil. Sure, if they found full RNA strands you'd start to think contamination was more likely, but what are the odds it was contaminated but with only uracil, especially considering how far they've gone to prevent contamination?
> For one, the spacecraft (or the empty capsules) could have been pre-contaminated before their launch.
I had a really interesting discussion with someone who oversaw decontamination protocols and preparations for various satellites, including the JWST. The protocols they use to prep satellites for these types of missions are beyond stringent, and the chemicals they use are exotic as all hell.
All this to say, contamination is absolutely possible, but there is so much insane behind the scenes work to control for it that it shouldn’t be thought of as something they might “just forget” or casually missed.
Remember the faster than light neutrinos that turned out to be a loose cable? I doubt they "just forgot", but being perfect is more difficult than making a mistake somewhere in the process. Before they publish I would hope they Quadruple checked for every source of possible contamination. Instead of saying we did it right so obviously nothing went wrong.
I think you're reading too much into the phrase "can be ruled out." I suspect that the leader author was saying "Contamination is possible, but based on our procedures, test methods, etc, the overwhelmingly larger probability is that we did detect <...> in the samples, and that the detection was not from pre- or post-contamination."
Could the paper's conclusions be incorrect? Yes, I think everyone--the authors included--will agree that "something could have gone wrong." But pointing out that "something could have gone wrong" is probably not a new idea to most readers.
“Scientists have previously found nucleobases and vitamins in certain carbon-rich meteorites, but there was always the question of contamination by exposure to the Earth’s environment,” said lead study author Yasuhiro Oba, associate professor at Hokkaido University in Japan, in a statement. “Since the Hayabusa2 spacecraft collected two samples directly from asteroid Ryugu and delivered them to Earth in sealed capsules, contamination can be ruled out.”
In other words, there is a history of finding similar compounds on meteorites but under circumstances that made it iffy, at best, to assert these compounds came from space. In spite of debate in comments on HN, this sample constitutes stronger support than we previously had for the idea that these compounds really exist on meteorites in space.
The thing I was hoping to see in the comments is discussion around the complexity of these compounds and thus how likely they are to form abiotic.
Looking at vitamin b3, it seems very simple.
My take away is more that the chemistry of life as we know it is pretty prevalent and probably forms readily under many circumstances. I am not shocked this wasn’t an actual DNA strand. Even if someone left some DNA out on an asteroid over enough time I expect it would deteriorate. The universe just bombards stuff without an atmosphere too much for naked DNA to survive in those conditions.
This is basically the biggest success I could rationally hope for from this probe. Great work for those scientists and I am so amazed!
I read Hoyle and Wikiramasingh's books back in the late 70s and 80s. Fun reads and thought-provoking no matter what side you fall on the Panspermia argument. To those who downplay it as not really being RNA, this is one mission to a near-Earth asteroid. What are the odds you would even find a nucleobase? Amazing work and the contamination argument is always presented in light of any such discoveries. There was also the dismissal of fossil-like impressions in meteorites cut open as just looking like a known life form. I WANT TO BELIEVE ;)
"The Japanese Aerospace Exploration Agency mission collected one sample from the asteroid’s surface in February 2019, then fired a copper 'bullet' into the asteroid to create a 33-foot (10-meter) wide impact crater."
10 meters seems like a pretty impressive crater for a science payload launched from a deep space probe. In case anyone else is curious, there's a detailed writeup[1] about the Small Carry-on Impactor (SCI) that was used.
It looks a little bit like a swords-into-plowshares version of a HEAT warhead. A shaped plastic explosive charge simultaneously launched and deformed a copper plate so that by the time it hit the asteroid, the projectile was shaped like a hollow bullet. ~2kg moving at ~2km/sec, so about 4 million Joules, or about 200 times the kinetic energy of a .50 BMG round. That's some bullet!
'''revealing that a wide range of organic compounds such as racemic non-protein type amino acids, alkylamines, carboxylic acids, polycyclic aromatic hydrocarbons (PAHs), and nitrogen heterocyclic molecules are present in the aqueous or organic extracts'''
from the linked paper.
racemic mix refers to the equal amout of stereoisomers
Given infinite time you would expect any pool of materials to eventually wibble together into certain compounds. Those compounds will wibble infinitely until they create structures. Some of those structures will be able to wibble compounds together. Some of those structures will be an exact copy of the structure that made it. Those structures will then replicate.
Simple life seems inevitable. It’s the tiers above that are the hard part. We only have mitochondria because we ate them and forced them to reproduce inside of us. Without that we would probably have never got beyond the single cell level. There’s a lot of random developments that we could have missed and ended up as just slime on a rock for eternity.
109 comments
[ 2.9 ms ] story [ 202 ms ] threadThe two main camps today seem to be "metabolism first" with people like Nick Lane and "genetics first" with people like Jack Szostack.
I used to favour the genetics side but I've been leaning more towards metabolism recently. Lane's research on this has been fascinating.
https://nick-lane.net/publications/
As for a good introduction to what his(and the many other people working in his lab) research is getting at, I really recommend the podcast episode he did on Sean Carroll's Mindscape podcast.
As RNA forms spontaneously with time, eventually you would end up with an RNA which can catalyse its own ingredients and replicate. As soon as you have one, it would replicate and take over the pool. Random changes would then lead to advancement.
Membranes also form spontaneously so the replicating RNA could find itself a bubble through random chance and live in it.
They can start mining asteroids for vitamins. /s
Crunchy rocks of breakfast cereal from the depths of space!
Delicious with cold milk.
Fortified with RNA compound and vitamin B3.
No added complex organic molecules.
Panspermia is a hypothesis that suggests life on Earth may have originated from microorganisms or organic matter that traveled through space, potentially from other planets or moons in our solar system or even from other star systems.
But where did the microorganisms on the asteroid come from?
It's an alternative explanation, but I'm not sure if this is evidence against panspermia either.
Every organic compound that spontaneously develops under natural conditions is an argument against the necessity of panspermia.
The opposite would be Earth was hit by other objects in the distant past, and the collision blew large chunks of Earth into space. Complete with B3 and RNA. (Especially credible as the body in question is a near Earth asteroid.)
All the posited explanations are reasonable hypotheses in my opinion.
Rather, IMHO, it gives us more information on how the conditions on Earth might have been when life emerged. We're getting more and more clues that a lot of the basic blocks of life are present in asteroids and thus might have been present on the primordial Earth as well in some watery soup where life emerged.
This is the theory of panspermia. No pseudo prefix required.
Edit: The wikipedia article breaks it down sufficiently, https://en.wikipedia.org/wiki/Panspermia
If your theory relies on external creation on another planet or whatever, then it’s meaningless because how did life start there. If life could start there then it could have started here so why do we need your theory at all?
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
miRNA are order of magnitude smaller.
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.
This is particular to stellar astrophysics. Astronomers studying asteroids maintain the conventional definition.
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' :)
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)
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.
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.).
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.
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.
Or evidence for the RNA world hypothesis [1].
[1] https://en.m.wikipedia.org/wiki/RNA_world
I seriously doubt that it could be "ruled out" just like that.
For one, the spacecraft (or the empty capsules) could have been pre-contaminated before their launch.
Second, the capsules could have been contaminated after arrival even if they were "sealed" (perhaps the seal had issues, or maybe it happened when they opened them, since one assumes they couldn't test still sealed capsules, they'd have to open them).
Yes, unimaginable that scientists could have made a mistake that a layman could spot, or just said something to create good PR to their mission, even when it's inaccurate.
They also never unwittingly or intentionally BS in their research papers, right? And only a colleague (or a higher level intellect than theirs) could spot a mistake... /s
>Seriously though, do you really think these scientists are making claims, being widely reported, without having made the same conclusions and analysed the situation with all the data, not just that reported through a story on the Internet .. ?
Seriously, similar blunders have happened time and again.
>Because it seems you're smarter than rocket scientists. Are you a brain surgeon, then?This particular case aside, you appear to believe that you need to be smarter than X person to be able to spot an error they made. It doesn't take a very high IQ however to see the error in the above idea.
In any case, based on the insults, did you just wanted to lash out on someone to feel better for yourself?
the way it currently reads is less like curiosity and more like “how dare you question the judgment of scientists”, as if questioning results isn’t the absolute bedrock of science in the first place
If a paper is published which claims that such-and-such drug shows effectiveness against shingles, it's easy and trivial to say, "Not so fast my friend" followed by any number of statements about Big Pharma, citing previous situations in which a claim was later shown to be false, etc. But while all of those things may, in fact, be true, they don't bring to bear any actual evidence that this particular drug study is flawed and exactly how.
It's also trivial to accept though. And in a world where you can't (for time and effort constrains) check every announcement personally, and where expert proclamations aren't always correct so thay you can just take them as granted, there are still reasons to have an estimation (as a layman but even as a scientist) of something being true or not summarily.
> I'd suggest reading every paper critically, realizing (as most people do) that the results are tentative, and either letting it go at that, or dig in and do the hard work to figure out what may be flawed in the work presented. Then work with the authors or publish a paper of one's own pointing out the flaw and the new resulting analysis.
yes, I agree, it would be better if they had a specific criticism of the methodology, but an appropriate response is simply to ask for such a thing, not to jump on them for questioning it at all, which is what happened here. do you see what I mean?
what happened:
>I think there could be contamination of the samples
>oh wow how adorable, what’s next from your big book of ideas, little one?
what would have been healthy:
>I think there could be contamination of the samples
>interesting. do you have a specific criticism of their methodology?
I also know that scientists have a bias to show impressive results, and that even NASA among others, in a similar case was all too fast to jump to conclusions and make a whole show about their 'findings' and annoucements to the press, and they still got it comically wrong, despite "actually working with the data and not just reading about it on the Internet.".
Finally, I know that "we found RNA building blocks and B3" on a meteorite is less likely that contamination, so the story seems fishy and premature.
Sorry that somebody even doubted than an announcement or a paper can ever be likely wrong without being on the team who wrote it.
Now how about some apologies for your tone?
Since you rightly encourage everyone to question claims, I question this claim. How do you know this, specifically?
In other words, we have a situation where a team has done a bunch of experiments, data collection, and analysis, and then published a paper claiming "we found RNA building blocks and B3", right? And now your claim is "no, you're wrong about that," but without any experiments, data collection, and analysis. So if you're going to make a claim, provide the details, data, and evidence that substantiates your claim.
Same, to give an obvious extreme example, as I'd be sceptical about an annoucencement that "We found the perpetual machine, there was a major flaw in thermodynamics laws, here are our numbers and results", even if they're world reknown experts in physics saying it, and I don't have access to their data, or to the machine to try it myself - hell, even if I can't understand their formulas.
One would still have a prior in this case, based on a general understanding of the the world, and the possibility range where this falls.
You might have a more informed prior because you took more concrete information into account than mere experience of other such announcements being repeatedly proven wrong, the probability of RNA being found on a meteor sample, the probability of the team just being lax with their annoucement to get publicity and grants, and so on.
Or, I guess, you think that we should never do that, and we should either do the research ourselves, or wait until someone else does, and at any point, whatever they say as their conclusion, them being experts and having done the work and everything, should be the final word.
Which probably means that as you see it, it makes no sense, to have a belief on anything or its refutation as likely or unlikely, unless one has either replicated the study and checked the conclusions, or found specific actionable faults.
> Finally, I know that "we found RNA building blocks and B3" on a meteorite is less likely that contamination, so the story seems fishy and premature.
Regardless of each of our own priors and biases, respectfully, you don't know this. You don't have evidence that shifts the probability in this direction. Or rather, you haven't presented any. You haven't pointed out a specific flaw in the experimental design, instrument design and operation, data collection and analysis. What you have done is state your strong prior suspicion that something is wrong. That's not knowledge, and it's nothing that anyone else could base their assessment upon. The statement is simply a statement of your prior, nothing else. It's not a material statement about the actual paper, its data, analysis, or its conclusion.
Actually its your tone-policing that is so disruptive to the conversation - you seem to have issues with peoples' statements given confidently - but fortunately there have been many more responses to your rash argumentation than I care to give.
There was a team / teams who planned the mission, designed and built the spacecraft and its systems & instruments, designed and performed tests on the samples, analyzed the data, and published a paper with some claims. The paper outlines their methods, test results, data, and conclusions.
Now, is it okay to question anything in the paper? Yes, absolutely.
How probable is it that something in the paper is wrong or could be improved? Definitely non-zero, it happens a lot. People who understand various aspects of the instruments used, the tests, data analysis, etc, often find some minor or major flaw in scientific papers. Could it happen with this one? Yes, absolutely.
How probable is it that someone on HN--knowing that there are lots of people on HN with diverse expertise--will find something wrong with the paper, and that the substance of the flaw they found is:
> I seriously doubt that it could be "ruled out" just like that.
> For one, the spacecraft (or the empty capsules) could have been pre-contaminated before their launch.
> Second, the capsules could have been contaminated after arrival even if they were "sealed" (perhaps the seal had issues, or maybe it happened when they opened them, since one assumes they couldn't test still sealed capsules, they'd have to open them).
Non-zero, but very low. Could it happen? Yes, it could very well be that the team(s) involved did not consider that contamination could occur before or after the sample was obtained and analyzed. How likely is it? Hard to say, but if it happened, the critique would not take the form of "Hey, it could have been contaminated!" Rather, it would take the form of "I notice in the sample handling procedure that such-and-such technique was applied. Further, in the data analysis, such-and-such test was not done, therefore one could not rule out ..."
You get the idea.
I merely gave a trivial (even exhaustive!) enumeration of possible contamination cases that could still have happened (regardless of whether they are targeted against in their protocols), not some novel avenue for contamination that I claim to be "smarter than the scientists" to come up with.
Of course they knew of those contamination possibilities. I didn't say anything about them having missed such basic contamination cases.
What I did (and am) suggesting is that they probably are too confident in their protocols having been executed correctly and being 100% tight with no possibility of error. And that that those avenues of contamination are still a real possibility (protocols to prevent them be damned).
Now, this might not be the case. This might indeed be space travelling RNA-combound and B3 vitamin.
But I'd say that the probability of contamination being the case and someone (on HN or wherever) calling it correctly, is equal to the probability of the samples being contaminated. Which is not that small.
Spotting some novel contamination route they haven't thought off would indeed be very rare and a major feat. But merely been less confident (that they are) in their thoroughness and in their preclusion of contamination, is much easier to claim and be correct while doing so.
But it's a trivial observation, and one that isn't actionable or testable. For the team to have designed and performed the instruments, experiments, data collection, and analysis to say "We're confident in our results and we have ruled out contamination" is substantive and is backed by data and actual experiments. For someone else to say, "I'm not so sure, I think it could have been contaminated," and then provide no actual argument or data on what could have gone wrong, is probably not a novel observation or comment. In addition, it's an easy thing to say (as you correctly point out) without putting oneself on the hook to show how or why.
Here's what I mean: we can confidently say about every paper ever published that "I'm not so sure." Here are the possible outcomes: (a) the paper stands the test of time, the result holds, and nobody remembers anyone who said "I'm not so sure," or (b) someone finds a flaw in the paper, works with the authors and they publish a retraction or revised paper, and then whoever said "I'm not so sure," can easily (as you say) point out how "they called it," all without doing any actual work.
I'd suggest reading every paper critically, realizing (as most people do) that the results are tentative, and either letting it go at that, or dig in and do the hard work to figure out what may be flawed in the work presented. Then work with the authors or publish a paper of one's own pointing out the flaw and the new resulting analysis.
Yes. But if they make a bold claim that "contamination can be ruled out", it's worth it to say to folks ready to take them for their word that, "it's still a possibility", even if it's not a testable finding but a suggestion.
Sure 'we can confidently say about every paper ever published that "I'm not so sure."'. But that doesn't mean we do say it for every paper ever published, or that we say it with equal weight.
The alternative is taking every research announcement at its word, and acting like it's true until it's taken down by another paper. And even then, why'd we trust the second paper refuting the first got it right?
In the end, it amounts to "if you didn't do the work or the review yourself, and din't find any specific actionable issue with it, then you should have no opinion about the probability of it being true or not".
Which is quite problematic. In the end, we often need and should be able to make a summary assessment of the possibility of a paper's conclusions being right or not (as based on our layman experience), even without working with the data, going through it with a fine comb or trying to replicate it, but based on a sense of probability of the conclusion, our knowledge of past assurances in similar statements being ultimately proven wrong, potential conflicts of interest, and so on.
Rather, I said when we read papers we should realize that results are tentative. It's fine to have some personal assessment of the probability, but it's not actionable by anyone, and communicating it doesn't assist in improving our collective assessment of what is going on in the world. I'd also suggest that we probably don't, in fact, "often need and should be able to make a summary assessment..."
Things like this do happen, and more frequently than one might expect.
I also didn't take a stance on this research. I've yet to read the paper, and I don't read "science journalism" like TFA. But it's not like the findings are earth shattering given previous research. Therefore I lean towards optimism.
I am simply saying that scepticism is warranted even if a paper is peer-reviewed and published in Nature. The "scientific process" doesn't magically end at peer review. The process goes on, and it pretty much never ends.
If your post was to point out a specific flaw, e.g., that the sample could have been pre- or post-contaminated, then it falls short of anything substantive and actionable. Nobody can do anything with it. Yes, you are correct. But no, there is not anything anyone can do with the critique. If you're going to point out a flaw, it needs to be something that you, the authors, or other PIs can check, perform, etc.
I first replied to a comment implying that just because research is widely publicised it should be accepted at face value, with a counterexample. That was all.
Then someone replied to that with the absurd implication I was somehow trying to denounce all of science based on that one example. I corrected them.
The only thing I said about this specific research was the following:
>>But it's not like the findings are earth shattering given previous research. Therefore I lean towards optimism.
If you inferred any other comment on the research than that, the source of that is your imagination, not anything I wrote.
> If your post was simply to say, "This paper could have flaws and its conclusions could be incorrect," then yes, almost all of us will agree with you. I'm not sure it's big news, however.
Critique doesn't just exist to be actionable.
It can also exist (as in this case) to remind of a possibility. Especially in this case, where the possibility is precluded.
In fact that was the very intended. Pre/post contamination could still have happened, we can't just exclude it because "protocols were followed". Protocols have been followed in other cases where errors got in the way to.
Perhaps you didn't wanted to see a general comment, but somebody spotting a specific error in a specific step of the actual process?
https://earth-planets-space.springeropen.com/articles/10.118...
I had a really interesting discussion with someone who oversaw decontamination protocols and preparations for various satellites, including the JWST. The protocols they use to prep satellites for these types of missions are beyond stringent, and the chemicals they use are exotic as all hell.
All this to say, contamination is absolutely possible, but there is so much insane behind the scenes work to control for it that it shouldn’t be thought of as something they might “just forget” or casually missed.
Could the paper's conclusions be incorrect? Yes, I think everyone--the authors included--will agree that "something could have gone wrong." But pointing out that "something could have gone wrong" is probably not a new idea to most readers.
https://earth-planets-space.springeropen.com/articles/10.118...
In other words, there is a history of finding similar compounds on meteorites but under circumstances that made it iffy, at best, to assert these compounds came from space. In spite of debate in comments on HN, this sample constitutes stronger support than we previously had for the idea that these compounds really exist on meteorites in space.
Looking at vitamin b3, it seems very simple.
My take away is more that the chemistry of life as we know it is pretty prevalent and probably forms readily under many circumstances. I am not shocked this wasn’t an actual DNA strand. Even if someone left some DNA out on an asteroid over enough time I expect it would deteriorate. The universe just bombards stuff without an atmosphere too much for naked DNA to survive in those conditions.
This is basically the biggest success I could rationally hope for from this probe. Great work for those scientists and I am so amazed!
10 meters seems like a pretty impressive crater for a science payload launched from a deep space probe. In case anyone else is curious, there's a detailed writeup[1] about the Small Carry-on Impactor (SCI) that was used.
It looks a little bit like a swords-into-plowshares version of a HEAT warhead. A shaped plastic explosive charge simultaneously launched and deformed a copper plate so that by the time it hit the asteroid, the projectile was shaped like a hollow bullet. ~2kg moving at ~2km/sec, so about 4 million Joules, or about 200 times the kinetic energy of a .50 BMG round. That's some bullet!
[1] https://www.planetary.org/articles/what-to-expect-hayabusa2-...
'''revealing that a wide range of organic compounds such as racemic non-protein type amino acids, alkylamines, carboxylic acids, polycyclic aromatic hydrocarbons (PAHs), and nitrogen heterocyclic molecules are present in the aqueous or organic extracts'''
from the linked paper.
racemic mix refers to the equal amout of stereoisomers
Simple life seems inevitable. It’s the tiers above that are the hard part. We only have mitochondria because we ate them and forced them to reproduce inside of us. Without that we would probably have never got beyond the single cell level. There’s a lot of random developments that we could have missed and ended up as just slime on a rock for eternity.