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First look at asteroid dust brought to Earth offers surprises
- uoaei 3y agoAromatic hydrocarbons! Expected, but still relieving to have evidence. Puts one more tally in the column of "life is probably carbon-based elsewhere, too".
- foruhar 3y agoPlease say more. What was this expected and how does it support the carbon-based hypothesis?
- bluGill 3y agoThis supports the hypothesis that the early molecules we think are needed to get to life happen elsewhere in the universe. There are only a few chemistries that could even support life. Carbon is the one we know the most about, and also one that we find the most evidence for getting to that complex of chemistry in the real universe. Nobody knows of course, but odds seem good if there is other life out there is it carbon based. (nobody really can know either - the universe is so far away we can't really detect details very well)
- psadri 3y agoHydrogen, carbon and oxygen are amongst the most common elements in the universe. So probabilistically life will be carbon based. And it will probably be first formed in water. But it would develop tools on land once opposing thumbs are formed (from climbing trees). So I think there is a high chance aliens with technology will look a lot like us.
- jvanderbot 3y agoSnakes climb trees.
- nomel 3y agoNot nearly as well as monkeys, or any other legged thing you can find in a tree.
- jvanderbot 3y agoI'd say leopards are probably the best tree climbers. Or squirrels. Not a thumb between them.
- deleted 3y ago[deleted]
- nomel 3y agoLeopards can't begin to approach what a monkey can do [1], since they can't hang safely, since they don't have thumbs. Leopards rely on penetration of their claws, or being on top of the branches, like squirrels. It works for the squirrel because they're small, and the tension forces applied to the bark are negligible, so they can just crawl upside down. You won't see a leopard hanging from anything, in a non-comical way. A leopard does have an advantage of clawing up thick trunks, which is one of the reasons they hunt monkeys that are first on the ground, rather already in the trees. [1] https://youtu.be/9rdn26Hpdwo?feature=shared&t=118 https://youtu.be/9rdn26Hpdwo?feature=shared&t=118
- jvanderbot 3y agoSpeaking of hanging, you know who really climbs trees well though? Sloths. Great at hanging. Practically live up there. No thumbs.
- deleted 3y ago[deleted]
- nomel 3y agoYes great at hanging, like a coat hanger. You can only easily pull with a hook. With a thumb, you can push, pull, and easily grip, with much less risk of "unhooking". That's the same risk for a leopard: unhooking. Sloth can't climb a thinner vertical rope, or hang from a thinner branch, because their grip strength is relatively weak, due to the leverage. And, good luck using any sort of tool, like a stick to get terminates, with giant hooked claws!
- albertsondev 3y agoThat logic follows... right up until the leap to arboreal lifeforms with opposable thumbs being an inevitability (or even a prerequisite to tool use!). Opposable thumbs are not a guarantee. Nor are tree-dwelling lifeforms, nor trees, nor thumbs, nor digits, nor four limbs. For all we know, intelligent life elsewhere might better resemble intelligent octopi using alkaline metals as their first rudimentary energy source as we did with fire.
- cmrdporcupine 3y agoWhy even assume multicelluarity as some kind of inevitability? Hell, it took 2 billion years to get to single celled eukaryotes on earth. But the earth was teaming with prokaryotes the whole time, two entire separate branches of them, too, and they seem to have sprung into existence almost as soon as the earth cooled enough. There's still a lot more of them in terms of total weight than animals and protists. A lot.
- psadri 3y agoIt’s not inevitable. I was simply stating the most probable form for the life that DID get that far.
- psadri 3y agoI was describing the most probable path, not the only path. I do think that developing more sophisticated tools under water is difficult. Once you have plants on land, taller “trees” are very probable, because they are competing for light. Once you have trees, it’s likely that animals will climb then for safety or food. Once they climb, they will likely develop better gripping, etc… I guess another way to look at this is that life on Earth is not special (although it is still an insanely amazing occurrence).
- anigbrowl 3y agohttps://www.usatoday.com/story/life/animalkind/2023/12/13/thumbed-dolphin-gulf-corinth-greece/71912925007/ https://www.usatoday.com/story/life/animalkind/2023/12/13/th...
- wolverine876 3y agoWhy do we assume land and trees, and everything required for them?
- andrewflnr 3y agoTrees, for one, have evolved convergently several times. You could arguably include those giant early fungus, too. Given land, trees will follow. Land mostly requires that your planet doesn't have too much water. Plate tectonics helps, but I'm not sure it's required.
- wolverine876 3y ago> Trees, for one, have evolved convergently several times. They evolved here. The whole question is how much their existence depends on Earth's specific environment, genetics, etc.
- deafpolygon 3y agoAt one point, this planet was covered in mushrooms!
- psadri 3y agoI think there are lots of worlds that don’t have dry land. I doubt they would develop advance technology - hard to build fire to melt metals. But perhaps nature will find another way?
- cocoa19 3y agoAbundant carbon is not the most compelling reason for aliens to be carbon based. Carbon is one of a few elements to be able to easily bind to other elements including itself and able to form long and complex chains. Silicon is another that can form long, complex chains.
- bluGill 3y agoBoth are needed. If it isn't abundant, then odds are against those long chains forming.
- somat 3y agoThe trace chemicals are even more interesting. Phosphorus while only needed in small amounts has a critical role in life as we know it. Phosphorus also turns out to be extremely rare in the known universe. to the point it is noteworthy to find a star that has it. https://www.sciencealert.com/lack-of-phosphorus-in-universe-is-bad-news-for-alien-life https://www.sciencealert.com/lack-of-phosphorus-in-universe-...
- bigbillheck 3y ago> it is noteworthy to find a star that has it. I don't think this is an accurate reading of that article. See forex https://arxiv.org/abs/1704.08282 https://arxiv.org/abs/1704.08282 whose abstract reads in part: > We also found average [P/Si] = 0.02 ± 0.07 and [P/S] = 0.15 ± 0.15 for our sample, showing no significant deviations from the solar ratios for [P/Si] and [P/S] ratios. Quoting from the introduction I find: Phosphorus abundances have been derived in planetary nebulae .... and in damped Lyman alpha systems using ionized phosphorus lines ... Anomalously high phosphorus abundances have been measured using optical phosphorus features in blue horizontal branch stars .... Molecular forms of phosphorus, such as PO, PN, and CP, have been detected and used to understand phosphorus chemistry in the interstellar medium ... or example, phosphorus molecules have been detected in the interstellar medium ... and in star forming regions ... Phosphorus molecules have also been found in the circumstellar envelopes of evolved stars (... Finally, the diffuse interstellar medium has been measured using P II lines....
- davideg 3y ago> Other, smaller chunks in the Bennu sample have light-coloured reflective coatings, making them seem brighter than the darker pebbles. But, under a scanning electron microscope, they were found to be covered in a highly brittle layer that broke easily, revealing a dark interior. Chemical analysis showed that this light-coloured surface skin contained magnesium, sodium and phosphate. This combination is rarely if ever seen in meteorites, Lauretta said. “It’s a head-scratcher right now.” Can anyone expound on which part of this is rare or what would be more expected? I'm guessing that if most meteorite samples are collected after impact on earth such a brittle crust would be destroyed before observation.
- throwup238 3y agoIt's rare to find volatile compounds like phosphate and sodium on the surface of a meteorite because they leach out and vaporize. It would make sense on a comet which form in the outer zone of our protoplanetary disk and shed their surface continuously due to all the water, but not a magnesium-rich asteroid that would have formed closer to the center of the solar system where the sun would have boiled volatile compounds off quickly, without a way for replacement compounds to migrate to the surface.
- LordGrey 3y ago> In October, researchers at the Johnson Space Center in Houston, Texas, discovered that 2 of the 35 screws that fasten the lid of the sample-return canister couldn’t be removed — blocking access to the remainder of the space rocks. That sounds about like every DIY repair around the house I attempt. Joking aside, the article goes on to say that "NASA is now making new screwdrivers" to gain access. Does anyone have details on this? Why would NASA need to build something new?
- yellow_lead 3y agoTo prevent contamination > The screwdrivers that NASA is building to free the remaining rocks and dust will need to be made from materials that won’t contaminate the samples, which are currently inside a nitrogen-filled glovebox. I'm not sure why the screwdrivers that opened the other screws wouldn't work though, if that's what you're asking.
- gumby 3y ago> Joking aside, the article goes on to say that "NASA is now making new screwdrivers" to gain access. Does anyone have details on this? Why would NASA need to build something new? They have to be qualified for use inside the glove box (read this in a different article), which I assume means sterile and unlikely to flake any material off. NASA is quite worried about being faked out by detecting something added post collection. Also who knows what the failure mode is, so here is some speculation: Perhaps some distortion in the case, so the screw holes are no longer circular? In which case the tool has to apply more torque than normal (without flaking or snapping) and maybe have a special clamp, and even a strain gauge for measuring torque?
- 303uru 3y agoSo as we discover that the goods for life are literally everywhere what's the rub? Intelligence is the big jump? Life is everywhere but hiding for some reason?
- anigbrowl 3y agoCould be it's just really hard to pick up life-transmitted signals from all the stellar noise. Obviously one would try to pick a quiet frequency, but transmission across light year distances would still need an awful lot of energy. Or maybe there's a space internet but we're just not aware of it yet.
- pishpash 3y agoOr space internet is locked behind a walled garden.
- deadbabe 3y agoI think we take it for granted that if your planet simply doesn’t have the right resources available, you’ll never truly have an Industrial Revolution. If there is life, it’s more probable it is stuck in some crude Stone Age state rather than high tech.
- BurningFrog 3y agoBoth the stone age and industrial resolution took over 4B years to produce from the ingredients.
- wolverine876 3y agoFor the industrial revolution: after 4B - really ~4.4999995 BY out of ~4.5 BY - arguably it only happened once in a very limited geographical area, and everyone else learned it from them.
- opportune 3y agoI struggle to think of a planet that wouldn't have the necessary ingredients for an industrial revolution. I don't think you need fossil fuels at all; on Earth, even without fossil fuels, we probably could have eventually gone from biofuels to wind/hydro power to solar/nuclear (these requiring a lot of energy for the refinement/processing of raw resources). It would have been a slow and gradual process, but if this process took about ~150 years with fossil fuels, I bet it would have only taken something like 500 years without them - a tiny blip in time, really. I think any planet capable of hosting carbon-based life would be able to at least produce wind energy, and probably most (assuming a rocky planet with liquid water and an atmosphere containing oxygen) would be able to develop all the energy types I mentioned. Solar and nuclear might be relatively less feasible if certain elements aren't common on that planet, and battery storage might also suffer from lack of resources. But wind and hydro alone are probably sufficient to eventually be able to develop controlled fusion down the line and have most energy-resource issues obviated. Even if you imagine some exotic form of life not like ours at all, on a planet that doesn't necessarily have water or an atmosphere, the life has to be able to derive energy from some kind of external source, whether it's by facilitating some chemical reaction like our deep sea micro-organisms or photosynthesis. Most likely that energy can be harvested in an automated fashion, and it's probably relatively abundant if life is able to evolve to the point of intelligence. For it to be completely inaccessible due to lack of resources, IMO you'd have to get into truly strange scenarios like intelligent life somehow developing in a nebula or the atmosphere of a gas giant.
- usernamegame 3y agoI am not sure why everyone is holding back on using the “L” word. The surface images of Bennu alone should have been enough. You can see the remains of what looks like marine animals (rocks shouldn’t have bilateral symmetry). The samples returned have amino acids which is exactly what proteins structures would decay to over billions of years. So bennu is likely remnants of a planet with life (either debris or an attempted seed packet). So let’s get this conversation moving! We only have 5 billion years left on earth. At the rate we are going we won’t have any of those critters named by then. -Not that anyone asked me but I recommend naming them all versions of either Cthulhu or Gilgamesh.
- fallingfrog 3y agoI’ve wondered sometimes why it is that asteroids are made out of anything as solid as rock, rather than just being big dust bunnies. I would assume that you would need pressure and heat to make rock, and therefore small rocky asteroids are derived from collisions between much larger objects.
- kbelder 3y agoIn space, if two small dust particles collide, they are probably moving at very high speed in relation to each other, and there's obviously no air to affect the impact. I don't know what that means, but I expect our intuition about how substances accrete is probably way out of whack.
- PM_me_your_math 3y ago[dead]