7 ms·
Ryugu asteroid samples contain all DNA and RNA building blocks
- pfdietz 8mo agoIt contains nucleobases. But does it contain ribose, or ribose linked to the nucleobases, or to phosphates? And more generally, does it also contain a grab bag of related chemicals that are not building blocks? The existence of such blocks as minor constituents of a soup of random chemicals doesn't mean much, especially as the concentration of any such constituent declines exponentially with its complexity.
- ceejayoz 8mo agohttps://www.nasa.gov/missions/osiris-rex/sugars-gum-stardust-found-in-nasas-asteroid-bennu-samples/ https://www.nasa.gov/missions/osiris-rex/sugars-gum-stardust... > The five-carbon sugar ribose and, for the first time in an extraterrestrial sample, six-carbon glucose were found. The soup does matter, as does finding that the ingredients are everywhere.
- pfdietz 8mo agoFinding exponentially decreasing amounts of specific chemicals is about as informative as finding short words in strings of random letters.
- ceejayoz 8mo agoFinding short words in strings of random letters at least establishes the existence of letters and words. It doesn't demonstrate the existence of Shakespeare's works, but it's a building block that's good to know exists.
- pfdietz 8mo agoAll it means is you can say "if life is rare, it's not because these specific small chemicals can't be produced". Which is a rather weak thing to say. It doesn't imply life isn't rare, or that further advancement the existence of these small building blocks is easy or inevitable.
- ceejayoz 8mo ago> All it means is you can say "if life is rare, it's not because these specific small chemicals can't be produced". This is absolutely a good finding to have in your pocket.
- pfdietz 8mo ago"Good"? Ok, if it makes you feel better. But scientifically, it doesn't do much.
- kakacik 8mo agoWhats your problem with this topic? Highly confronting posts about nothing. Iterative approach to science seems foreign here.
- pfdietz 8mo agoThere's a tremendous amount of confidently stated bullshit on the issue of OoL that I have long since lost all patience with. What's your problem with the debunking of falsehood?
- HarHarVeryFunny 8mo agoIt's a sample of one, but I think the takeaway is just that if the nucleobases are present on a random asteroid then they probably commonly occur. Of course as you note it takes a lot more than that to form these into nucleic acids. I would guess there is a more primitive stage in the emergence of life where self-replicating soups (Kaufmann: metabolisms), including things like nucleobases and amino acids, capable of collective replication/expansion exist, before we get anything as sophisticated as nucleic acids and structural encoding.
- zenon_paradox 8mo ago[dead]
- hmokiguess 8mo agoHow are samples collected? In space or as debris?
- sheikhnbake 8mo agoSurface sample: Hayabusa2's sampling device is based on Hayabusa's. The first surface sample retrieval was conducted on 21 February 2019, which began with the spacecraft's descent, approaching the surface of the asteroid. When the sampler horn attached to Hayabusa2's underside touched the surface, a 5 g (0.18 oz) tantalum projectile (bullet) was fired at 300 m/s (980 ft/s) into the surface.[72] The resulting ejected materials were collected by a "catcher" at the top of the horn, which the ejecta reached under their own momentum under microgravity conditions. Sub-Surface Sample: The sub-surface sample collection required an impactor to create a crater in order to retrieve material under the surface, not subjected to space weathering. This required removing a large volume of surface material with a powerful impactor. For this purpose, Hayabusa2 deployed on 5 April 2019 a free-flying gun with one "bullet", called the Small Carry-on Impactor (SCI); the system contained a 2.5 kg (5.5 lb) copper projectile, shot onto the surface with an explosive propellant charge. Following SCI deployment, Hayabusa2 also left behind a deployable camera (DCAM3)[Note 1] to observe and map the precise location of the SCI impact, while the orbiter maneuvered to the far side of the asteroid to avoid being hit by debris from the impact. It was expected that the SCI deployment would induce seismic shaking of the asteroid, a process considered important in the resurfacing of small airless bodies. However, post-impact images from the spacecraft revealed that little shaking had occurred, indicating the asteroid was significantly less cohesive than was expected.[76] Duration: 36 seconds.0:36 The touchdown on and sampling of Ryugu on 11 July Approximately 40 minutes after separation, when the spacecraft was at a safe distance, the impactor was fired into the asteroid surface by detonating a 4.5 kg (9.9 lb) shaped charge of plasticized HMX for acceleration.[56][77] The copper impactor was shot onto the surface from an altitude of about 500 m (1,600 ft) and it excavated a crater of about 10 m (33 ft) in diameter, exposing pristine material.[15][32] The next step was the deployment on 4 June 2019 of a reflective target marker in the area near the crater to assist with navigation and descent.[33] The touchdown and sampling took place on 11 July 2019.[34] https://en.wikipedia.org/wiki/Hayabusa2#Sampling https://en.wikipedia.org/wiki/Hayabusa2#Sampling
- 8mo ago
- 0x000xca0xfe 8mo agoOne longstanding theory is that life first began on Earth when asteroids carrying fundamental elements crashed into our planet long ago. I'm no expert but this sounds strange. Surely those fundamental elements would also form in vast quantities on their own on an entire planet with volcanoes and oceans? Wouldn't a couple asteroids be the literal drop in the ocean in comparison? The missing part is how do they form self-replicating mechanisms capable of evolution. I doubt an asteroid with a bit of organic dust is enough for that. If such small amounts suffice we should see the formation of new life forms from scratch, today, left and right I think?
- starburst 8mo agoWell the competition might be too fierce for any new life to develop
- 0x000xca0xfe 8mo agoWe could artificially create a sterile, large pool of the ingredients and see what happens. I've read about experiments like this but only at lab beaker scale.
- pixl97 8mo agoThe bigger the pool the harder to create it here on Earth without introducing problems. For example, take a prion. Hard as hell to actually get rid of, how do you know you've not actually introduced something like this to your sterile pool that's going to make it do things you don't expect.
- HarHarVeryFunny 8mo agoYeah, but it seems impossible to experiment on the scale that would have happened in nature where there would have been millions of localized "test tube experiments" ongoing for millions of years. Of course people can, and do, try to replicate early earth environments and self-assembling proto-cells, but I'm not sure how intellectually satisfying any self-replication success from these "designer experiments" would be, unless perhaps done on such a large scale (simulation vs test tube?) that any conclusions could be made about what likely happened in nature - just how specific do the conditions need to be?
- fusslo 8mo agoI wonder how they prevent contamination of the containers used to collect and store samples. I assume they have to be ultra clean in every sense of the word 'clean' with the cavity pulled to a vacuum. And also the equipment that collects the sample and puts it into the canister has to be clean as well. The logistics aren't obvious to me at all
- ceejayoz 8mo agoThey seem pretty confident. There's been some conflicting reporting on contamination of the Ryugu samples over time. https://phys.org/news/2024-11-ryugu-asteroid-sample-rapidly-colonized.html https://phys.org/news/2024-11-ryugu-asteroid-sample-rapidly-... > Researchers from Imperial College London have discovered that a space-returned sample from asteroid Ryugu was rapidly colonized by terrestrial microorganisms, even under stringent contamination control measures. https://www.isas.jaxa.jp/en/topics/003899.html https://www.isas.jaxa.jp/en/topics/003899.html > As described in the discussion of the journal paper, all samples received from JAXA have undergone the initial description, storage, and sealing in dedicated containers under a nitrogen atmosphere. The samples are distributed to researchers without exposure to the Earth's atmosphere. The possibility of microbial contamination is therefore considered extremely low. In addition, organic and microbial contamination assessment of the environment at the curation facilities within JAXA (clean chamber) in which the Ryugu sample grains undergo the initial description are conducted 1 ~ 2 times a year. It has been confirmed and reported that the concentration of organic matter is at or below the same level as that of the OSIRIS-REx asteroid return sample glove box at the NASA Johnson Space Center, and that no microbial colonies have been detected in the microbial contamination assessment conducted with swabbing and culture medium (Yada et al., 2023). Based on these facts, we agree that the microbial contamination described in the paper did not occur during a process within JAXA, but under the laboratory environment of the allocated researchers.
- fusslo 8mo agoty ty! I usually just give a quick chatgpt buy my work blocked every ai but copilot
- _ink_ 8mo agoAre these building blocks not evaporated on impact?
- deleted 8mo ago[deleted]
- stouset 8mo agoOnly the outer surface of asteroids gets hot. Atmospheric entry isn’t long enough to thoroughly cook a rock.
- drob518 8mo agoWhat about the immense energy that is released when it slams into the earth at supersonic speeds?
- Symmetry 8mo agoA asteroid has to be absolutely huge to make it all the way down to the surface without slowing down to terminal velocity. Your typical 1kg asteroid will have slowed to terminal velocity dozens of km above the surface. The smaller an object the lower the ratio of its mass to surface area and the more easily it slows down.
- johnsmalles 8mo agoFascinating that all five nucleobases were found in Ryugu samples. The fact that these formed abiotically in an asteroid environment strengthens the case that the building blocks of life are common throughout the solar system. The amino acid findings from the same samples were already compelling, but having the complete nucleobase set is a different level of evidence.
- deleted 8mo ago[deleted]
- pfdietz 8mo agoRyugu showed an estimated ~20,000 different organic molecules. It's not that surprising that the nucleobases would be among them, along with all sorts of chemicals not relevant to life. https://www.science.org/doi/10.1126/science.abn9033 https://www.science.org/doi/10.1126/science.abn9033 In the reference from the link for this HN entry, we see the nucleobases were present at concentrations of about 1 nano-mole per gram (< 1 ppm). They are minor constituents present in a sea of mostly non-biologically relevant compounds.
- qsera 8mo agoDoesn't multi-world interpretation pretty much answer how life originated? I mean, even if the starting state require to bootstrap life have impossibly low chance to happen random, multi-world interpretation implies that there will be some worlds where it happened, and observation of life is only possible in such worlds..
- kmaitreys 8mo agoMulti-worlds is not really relevant here. You are just asking the question how the building blocks of life form in the Universe and how can they reach a planet like ours.
- qsera 8mo agoI mean, Multi worlds is the only way this impossibly random event can occur on its own.
- kstrauser 8mo agoThat's not true. If life has the odds of one in a quadrillion of happening, and we're here to discuss it, then we're that one in a quadrillion. If we weren't, we wouldn't be alive. By definition, we were the lucky ones with the perfect conditions that resulted in us.
- qsera 8mo agoThat is what I meant. But I don't think we are "lucky", because we are part of the world, not something that was placed inside it by choice. It is like asking why is Nile in Egypt and not in some other place. If Nile is in some other place, it would not be Nile...So does it make sense to say that Nile is lucky to be in Egypt? No, I think it does not make sense...
- jibal 8mo agoSorry, but nothing you have said here is true or makes sense. Multi worlds are universes, not worlds within our universe. The multiworld interpretation is one of several interpretations of quantum mechanics of the exact same evidence--one or the other interpretation being "true" has no empirical implications. And it is an interpretation of quantum mechanics, which has nothing to do with the distribution of nucleotides. And it's incoherent to call an observed event "impossible". You seem to mean that you think that it is highly unlikely, but offer no reason to think so ... nor for the bizarre claim that "Multi worlds is the only way". I suspect that you are mixing up a very confused understanding of "Multi worlds" with some version of the anthropic principle. But the anthropic principle is an a posteriori explanation of an a priori unlikely occurrence, it's not a "way" for something to happen. I won't comment further unless you offer a convincing proof of your assertion.
- shevy-java 8mo agoThat's not really new. It seems as if some people try to project "there is life outside of planet Earth". Well, the thing is ... is this question important? You already have life here. Synthetic biology will also progress. So why is it important if life is anywhere else? I don't understand it. There is nothing magic in RNA or DNA. Granted, right now we can not easily explain how life gets "bootstrapped", but recently there was a paper of self-propagating RNA even of a kind of semi-random sequence; this RNA can just amplify itself. I am sure you can find many more similar examples eventually as well as biochemical reaction processes that can be "bootstrapped" - and I am also sure none of these work on an asteroid. So why is there this strange focus on "life outside of planet Earth"? Some people want research money, that is clear now.
- georgemcbay 8mo ago> It seems as if some people try to project "there is life outside of planet Earth". Well, the thing is ... is this question important? You already have life here. How common the building blocks of life are out in the universe has important implications for open questions like the intersection of the Drake Equation and the Fermi paradox which has likely relevance to our own future here on Earth. ...though I happen to think what we know so far isn't comforting in the sense that the building blocks of life do appear to be very common and the most likely reason that we have to ask "Where is everybody?" in spite of that is that the Great Filter is probably expansionist self-destruction of the sort we are currently speed-running as a society.
- asdff 8mo agoWhy study anything new? You survived this far without it, after all :)
- stevenjgarner 8mo agoUmmm ... the "Victoria University of Wellington in Australia"? Please. Victoria University is located in Wellington, New Zealand [1]. Nothing to do with Australia. Dr. Morgan Cable is a Senior Lecturer in Space Science at Te Herenga Waka, Victoria University of Wellington in New Zealand [2]. Can't believe that phys.org would publish such an error. [1] https://www.wgtn.ac.nz/ https://www.wgtn.ac.nz/ [2] https://www.psi.edu/staff/profile/morgan-cable/ https://www.psi.edu/staff/profile/morgan-cable/
- parallax_error 8mo agoFirst time I’ve seen my university mentioned online and it’s the wrong country!
- Amorymeltzer 8mo agoI'm in the middle of reading Peter Brannen's The Story of CO2 Is the Story of Everything—it's excellent and goes deep into the (bio)geochemistry of Earth—and he presents a good case for a metabolism-first development of life, taking advantage of "a disequilibrium that needed to be relieved at the vents, an unending stream d free energy to dissipate," rather than the RNA information-first theories. It fits his overall narrative but it was an interesting way to think about life "as a thermodynamically necessary mechanism to relieve the continuous production of free geochemical energy on Earth... more efficiently than abiotic processes could." (Brannen quoting complex-systems scientist Anne-Marie Grisogono) I highly recommend the book.
- cmrdporcupine 8mo agoThis is similar to Nick Lane's books, and the research he references as well. The necessity for disequilibrium, the emphasis on life as the movement of energy across a barrier, etc. I'm no expert but it seems most reasonable to me. The continual talk about pre-biotic soups of ingredients seems profoundly misplaced.
- api 8mo agoI’ve wondered before if the idea that life originated on Earth might be the last geocentrism to fall. Speculation of course, but it would fit a certain historical pattern. Maybe life is all over the damn place, just a thing that happens under certain thermodynamic constraints, and it arrived on board comets or some similar mechanism. Maybe space contains spores of minimal super simple organisms that can survive being vacuum freeze dried for incredibly long periods of time. When they land somewhere suitable they do stuff. Maybe life originated long, long ago. The wildest speculation I have is that it originated shortly after the big bang during a brief period when the temperature of the universe was temperate, but that’s very far fetched for numerous reasons. More likely that it pops up from time to time and spreads over cosmic time scales. But it only evolves to high levels of complexity in environments that are very friendly to a lot of life, have abundant energy, and are stable enough for a very long time. That may be the rare thing.
- brcmthrowaway 8mo agoAnyone else think a universal intelligence is behind seeding planets with these rocks?
- SenHeng 8mo agoLike a god? No. Or like some ancient alien species that travelled the stars but found it was alone, like in the ST:TNG episode[0]? No too. Even if these ancient aliens thought it would be fun to spread their sperm all over asteroids and fling them out into the universe, there wouldn't be enough time for those rocks to get anywhere. The more logical conclusion is that abiogenesis happens everywhere in the universe under the right conditions. [0]: https://en.wikipedia.org/wiki/The_Chase_(Star_Trek:_The_Next_Generation) https://en.wikipedia.org/wiki/The_Chase_(Star_Trek:_The_Next...
- jibal 8mo agoNo one with any sense.
- nikolay 8mo agoSo what?! This does not prove anything! There are stones all around us, but they don't assemble themselves into beautiful, majestic stone buildings! All ingredients of concrete are around us, but we don't see them turning into concrete and pouring themselves into freeways, bridges, and all kinds of much less complex than living organisms!
- kakacik 8mo agoSo what? We are not really experienced in judging how chemical processes work across (a half of) billion year timespan. Or how can intense lighting and volcanic activity across similar timespans affect the probabilities of outcomes. And so on
- nikolay 8mo agoWhy is this process not ongoing now, then, when there are tons of prefab elements of life, i.e., it should be easier today than it was a billion years ago? A billion years is not as long as you think!
- tengbretson 8mo agoI just walked into a room and everywhere I look, everything I see is made up of the same basic building blocks. The only thing left to figure out is how did these legos learn to assemble themselves.
- Shitty-kitty 8mo agoThe most important question we all want answered is just how rare life is in the Universe. The fact that the building blocks are there just floating around on asteroids makes it that much more likely that its quite common.
- nephihaha 8mo agoFred Hoyle suggested this back in the seventies and eighties and was berated for it.
- pfdietz 8mo agoIf you look at the paper, the nucleobases were present at concentrations of about 1 nanomole per gram. So, maybe 200 ppb by mass for each. They are in a sea of other random organic stuff that is at best tangentially relevant to life as we know it.