13 ms·
New study dramatically narrows the search for advanced life in the universe
- hurrdurr2 7y agoThis study seems rather self limiting (but then again I'm no biologist)... what if there are non-carbon based life that does not care about carbon dioxide or carbon monoxide?
- hurrdurr2 7y agoThis is off topic, but I am almost done with the book The Dark Forest, and the concept kind of terrifies me regarding extraterrestrial life.
- djohnston 7y agowe just need to stay quiet
- andrewflnr 7y agoYeah, Voyager's already gone, it's too late.
- quotemstr 7y agoVoyager is also very slow and will soon be very cold. I wouldn't worry. The book's premise relies on fictional physics pretty far from anything we know in the real world --- things that would cause all sorts of thermodynamic and information-theoretic havoc --- so I wouldn't worry.
- richk449 7y agoYou think that’s scary, just wait until you watch Jaws. Giant shark will eat you up.
- abrookewood 7y agoIt's a great series.
- kabdib 7y agoThe wide range of extremophiles here on earth makes me think that this paper is parochial, at best. Carbon is versatile and oxygen is a great source of energy, but that doesn't preclude other biochemical systems. Given the amount of real estate in the universe that is "out in the cold" (Oort cloud equivalents, way beyond the snow line) it may be that we are the oddballs, and there are scientists out there wondering how life would be possible with molten ice and burning things with something as hellishly reactive as atomic oxygen. Free-floating planets might be where the really good parties are in our galaxy.
- fhars 7y ago“They are made out of meat” http://www.eastoftheweb.com/short-stories/UBooks/TheyMade.shtml http://www.eastoftheweb.com/short-stories/UBooks/TheyMade.sh...
- throwaway743 7y agoThat was beautiful. Thank you for the good laugh
- Fricken 7y agoWouldn't the best place to look for life be right here on Earth? I mean, if it could be demonstrated that life has or had more than a single origin on Earth, then we'd have 2 data points, and it would suggest that under the right conditions the emergence of life is not an anomalous occurrence.
- onion2k 7y agoThe study doesn't dispute that. Any planet with any conditions could host complex life that's beyond our understanding. That's not helpful in a search. If we're going to go looking for extraterrestrials then we need to narrow the search to parameters we can recognise, and looking for "life as we know it" seems a reasonable starting point. Essentially the point is to be self-limiting. No one is saying "Planets outside of these parameters can't have complex life." but instead "Planets outside of these parameters could not give rise to what we know as complex life."
- marcosdumay 7y agoIt's really pushing the envelope to assume that "life as we know it" consists on animals with a circulatory system that uses hemoglobin and blood with neutral PH. Why would life depend on the low concentration that is not even toxic to all of the life here on Earth?
- onion2k 7y agoWhy would life depend on the low concentration that is not even toxic to all of the life here on Earth? It wouldn't, and the study isn't saying that it would. The point is about narrowing the search space. An analogy would be guessing passwords. If I want to guess the passwords of the people I work with I can start with the assumption that it could be anything, which doesn't narrow the space and makes the task impossible, or I can start with the assumption that it'll be based on a dictionary word with some numbers because all my passwords are like that. I'll definitely miss some passwords that don't fit my assumption but I'm far more likely to get some positive results (assuming my way of generating a password is common in the universe.)
- mannykannot 7y agoFair enough, but it would be counter-productive to have too restrictive a filter. Take the CO criterion, for example. While it is reasonable to point out that CO may be present in high concentrations in many planetary atmospheres, at levels that would be toxic to life evolved on earth, one must consider that life might evolve in a way that tolerates or even exploits it. Oddly, the authors acknowledge this, yet, apparently without any counter-argument, still include CO as a probable show-stopper. As the way to search for life beyond the solar system is to look at atmospheric composition, an alternative way to look at the 'CO problem' is to say that an abnormally low CO level on these planets might be a hint of life.
- marcosdumay 7y agoThere is plenty of life that doesn't care about carbon dioxide and monoxide here on Earth. When life started here CO2 was from hundreds of thousands to many millions of times more abundant than it's now. Tens of thousands more of it won't probably even make oxygen respiration impossible.
- kupopuffs 7y agoSource? All indirectly depend on carbon dioxide (through photosynthesis).
- YaxelPerez 7y agoEcosystems at the bottom of oceanic trenches rely on energy from volcanic vents (chemosynthesis) instead of photosynthesis
- kupopuffs 7y agoFascinating! Although chemosynthesis uses CO2, I did not expect Methane to be a carbon source
- marcosdumay 7y agoHum... There is plenty of life that don't care about high concentration of those gases.
- kupopuffs 7y agoYes, like humans we don't care about CO2, but we depend on creatures that indirectly or directly use it.
- Balgair 7y agoDeep sea vents are not dependant on the photosyntheic carbon cycle. https://en.wikipedia.org/wiki/Hydrothermal_vent#The_Deep_Hot_Biosphere https://en.wikipedia.org/wiki/Hydrothermal_vent#The_Deep_Hot... Other extremophiles and archea exist and have been observed in deep caves and rocks. Life really does find a way!
- m3kw9 7y agoYou got to go with what you know.
- andrewflnr 7y agoAnd if what you know is nothing, you accept that, rather than speculate based on arbitrary assumptions.
- p1necone 7y agoWe're not looking for all life. We're looking for any life.
- rjf72 7y agoBut this study does not do that. What we know is that life on this planet evolved to the conditions of this planet. As the conditions of the planet changed, which they have and quite radically, so too did the life. Life didn't evolve to breathe nitrogen, oxygen, etc which we just coincidentally had - it evolved to breathe and utilize what was already present on our planet. And this should be the assumption for all life, which means that restricting stuff because it would be inhospitable to us is completely nonsensical.
- vertline3 7y ago"non-carbon based life" I guess isn't silicon the only other that bonds four ways? Not a chemist but I feel that 4 bonds are a big thing.
- teucris 7y agoI had a debate about this with a friend - is there a chemical cycle using silicon that could work like respiration does for organic life? Silicon dioxide is, well, glass...
- p1necone 7y agoAre you referring to it being a solid? Silicon dioxide would be a gas at some temperature - likewise CO2 is solid below -78.5c. Extraterrestrial life doesn't have to be anywhere near the same temperatures as us. Also I don't see why you couldn't have an organism that "breathes" solid material.
- m1el 7y agoI researched this topic for a while, and I came to conclusion that Si-based life is nearly impossible for several reasons. > Silicon dioxide melting point: 1710 °C No complex chemistry can survive these temperatures. SiO2 is only soluble in HCl and HF, which are very reactive, so no solubility either. > Also I don't see why you couldn't have an organism that "breathes" solid material. All of known biological chemistry relies on some sort of solubility for reagents. I don't think there's any known organism that can get rid of solid waste from the entire volume of the organism.
- ars 7y agoYou could react silicon with fluoride instead of oxygen. Silicon tetrafluoride melts at −90 °C (and boils at -86). You can also have chlorine as your oxidizer and make Silicon tetrachloride which melts at −68.74 °C and boils at 57.65 °C, that temperature range is perfect. What else will change by having a chlorine instead of oxygen atmosphere?
- Balgair 7y agoIn terms of life that is made out of 'normal matter' like we are, there are a few different universal solvents that could make this work [0]. Wikipedia's entry there is fairly facinating stuff. The really big take-away is that there is a limited number of universal solvents and we know what the temperature and pressure ranges of those solvents are; there are defined 'Goldilocks Zones'. Outside of the matter that we are made of, who knows. It's not impossible that dark matter could somehow be set-up to create life, but we've no idea if it's feasible. The same goes for dark energy, only more so as we have basically no clue what dark energy is, even though it makes up the majority of the 'stuff' in the cosmos. [0] https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Non-water_solvents https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi...
- pharrington 7y agolink to actual study: https://iopscience.iop.org/article/10.3847/1538-4357/ab1d52 https://iopscience.iop.org/article/10.3847/1538-4357/ab1d52
- mensetmanusman 7y agoWhat if future humans check all the planets in the universe and find no other life
- vcavallo 7y agoreal fuckin bummer!
- toomuchtodo 7y agoWe move on to the next universe to continue the search. Stay curious.
- aristophenes 7y agoToo narrow minded. We create our own new life, of course. Then watch the smartest ones convince the rest that we don't exist.
- aristophenes 7y agoImagine an AI without access to external sensors or knowledge of humans. Would they believe in a maker?
- deleted 7y ago[deleted]
- D-Coder 7y agoThen we get to own them all!
- onion2k 7y agoGoing by human history the fact there is intelligent indigenous life somewhere doesn't stop some of us deciding we own it.
- 7y ago
- ianai 7y agoThis still sounds like an overly pessimistic crowd of suppositions. I was hoping for inferences into planetary atmospheres. It’s probably mostly impossible, but I think I’ve seen estimates on some of these planets atmospheres. Until, if we can ever, measure what’s in the atmospheres of these planets we’re really stretching it.
- maxander 7y agoSeveral bars of CO2 are inhospitable to life evolved in an atmosphere of several hundred ppm of CO2, sure, but are there arguments that high levels of CO2 would be detrimental most possible lifeforms out there? (CO is much more reactive, but it's harmful to us because it reacts to our hemoglobin in much the same way as oxygen. So since Earth life has managed to get on just fine with all this corrosive oxygen around, the same argument may still apply.)
- scythe 7y agoI think so, actually. The reason is that usually carbon-based life gets its carbon from CO2. But life doesn't stop growing because it's going to kill itself, cf. global warming. So photosynthesis on these planets might continue until their atmosphere is drained of CO2 and they freeze. Then again, I suppose there could be an equilibrium, but that equilibrium would require the planet to remain "uncomfortably" cold to suppress photosynthesis. Of course, that's a completely different argument from the one the researchers had.
- ailideex 7y agoHas this not happened on earth already? First plants caused ice ages, new research reveals : https://www.sciencedaily.com/releases/2012/02/120201094923.htm https://www.sciencedaily.com/releases/2012/02/120201094923.h...
- azernik 7y agoYup! And then we reached a (very-low-carbon) equilibrium.
- deleted 7y ago[deleted]
- deleted 7y ago[deleted]
- yread 7y ago
- idlewords 7y agoThis study makes extensive assumptions about life on other planets being earthlike. Boy will we have egg on our face when the xenonauts land on earth with their breathing tanks full of carbon monoxide.
- andrewflnr 7y agoI'd be curious to see an outline of a metabolism based on CO. Can you build an analogue of hemoglobin that behaves nicely with CO?
- idlewords 7y agoWe wouldn't know how to build anything at that level of complexity. We can only study and modify molecules that evolution found here on earth, which severely limits our ability to imagine anything truly different.
- hoseja 7y agoWho says there has to be anything resembling hemoglobin? Or blood? All this xenobiology is so shortsighted.
- andrewflnr 7y agoCirculating fluids are super convenient for moving chemicals around. Plants use them, too. I would be very surprised if there wasn't at least an analogue for blood.
- scarejunba 7y ago> This study makes extensive assumptions about life on other planets being earthlike. That's the point. When you can't find your keys at work, there are a wide range of possibilities - in reality, an infinite such number. But they're probably somewhere in the clutter on your desk.
- mxcrossb 7y agoCoincidentally, a paper was published today in Reviews of Modern Physics on this topic: https://link.aps.org/doi/10.1103/RevModPhys.91.021002 https://link.aps.org/doi/10.1103/RevModPhys.91.021002 https://arxiv.org/abs/1810.02007 https://arxiv.org/abs/1810.02007 It seems like a fun time for this field
- julius_set 7y agoI mean that’s all well and dandy but as the article itself mentions: “these parameters are toxic to human and animal life on Earth.” Your definition and data for life is only the current life on Earth, since we don’t have a clear understanding of other types of life in the universe we cannot fully support this hypothesis.
- rdiddly 7y agoYep, all the obvious disclaimers apply regarding the acid-breathing snail-people of Xebron 5...
- _Codemonkeyism 7y agoXebron 6.
- ddxxdd 7y agoI prefer to imagine alien life as a sentient sludge with internal electrical signals as complex as the human brain, but with no notion of "self", "emotion", "purpose", "language", or other silly human things. Heck, what's stopping us from classifying ocean currents as a sentient lifeform?
- sweetheart 7y agoYou should read Children of Time and then Children of Ruin.
- dr_dshiv 7y agoArguments for panspermia could go either way. If panspermia is designed, it might be tailored to a wider range of conditions. If "natural", it is more likely to have a chemistry like ours, based on the one spurious data point we have available
- raxxorrax 7y agoSo do we have a weakness in processing larger amounts of co2 because we have low levels in our athmosphere or is this a fundamental problem that respiratory systems cannot handle? I mean water didn't stop us.
- akvadrako 7y agoDuring the Ordovician period, a few hundred million years ago, CO2 concentrations were around 4,000 - 6,000 ppm, and there was plenty of animal life. At the low end, the article is talking about 10,000 ppm (0.01 bar), so not much higher.
- raxxorrax 7y agoYeah, I would think that is still okay for life. Even if CO2 does displace O2, I would imagine some adapted respiratory organs could very well deal with that if the concentration were higher.
- negamax 7y agoIt's strange to make this hypothesis. We know so little about life. What if life can exists anywhere and can adapt to its environment. Even the complex one
- nurettin 7y agoWhat scientists appear to be telling us is that this is "life as we know it", without delving much into the details of what life could constitute of. And that conventional definition of life, which requires very specific aminoacids to co-exist, is pretty much dependent on certain mixes of humidity and temperature and certain gases are toxic to it in general.
- marcus_holmes 7y agoAlso, life adapts its environment to suit it, as the Gaia theory posits.
- vixen99 7y ago"...high concentrations of carbon monoxide, another deadly gas" could have been phrased rather differently given that this 'deadly gas' is essential for life on earth at around >150ppm or so and without which almost all plants would die in short order never mind that respiration likewise for plants and animals involves its excretion along with water. There is no such thing as a single chemical substance that is <not> toxic for life forms at some concentration. Yes, there are optimum levels for all of them - in some cases down to almost zero.
- sktrdie 7y agoI think life (event from chemistry to biochemistry) is rare because we can think of each planet as a specific combination of chemistry composition. All these combinations, even if they exist in the order of billions, is still a limited amount of possible combinations of chemical properties. In a lab we can reproduce these combinations in ideally a much greater number. So my insight is that we can create chemical processes in a lab at a much higher rate and with much more interesting combinations that nature can. And still life hasn't arose in the lab. This seems to me like a sensible experiment that can somewhat prove that if we can't do it in the lab, where we're free to combine whatever we want, then why should it be "easy" for nature with its limited amount of combinations.
- vikramkr 7y agoBecause nature has way more time and space than we do. And life hasn't arisen in the lab (on earth by humans at least) yet, but it's certainly arisen in nature at least once, so those factors seem to clearly outweigh our ability to experiment
- agumonkey 7y agoBut Nature doesn't optimize for life. It had billions of years and insane amount of space to do whatever. We ~may be able to focus search on life sustaining chemical combinations ?
- vikramkr 7y agoNature does optimize for life because by definition the result of any optimization is life. Natural selection is a powerful force. And with time, nature optimizes for chemical reactions that self replicate without the biases and weaknesses of human science. We aren't patient enough to wait as long as nature is willing to and we are biased because we keep trying to replicate life like ours. Nature also had panspermia and other techniques to spread life around once it gets going, it only needs to figure it out like once per galaxy under some sets of assumptions
- MichaelMoser123 7y agoWhat happened to the theory that you need a moon with its tides? Is that still credible or is it not? https://www.scientificamerican.com/article/moon-life-tides/ https://www.scientificamerican.com/article/moon-life-tides/
- gjm11 7y agoThe phys.org article just reproduces (while adding a bunch of irrelevant internal links and some advertisements) the university's press release here: https://news.ucr.edu/articles/2019/06/10/new-study-dramatically-narrows-search-advanced-life-universe https://news.ucr.edu/articles/2019/06/10/new-study-dramatica... and the actual paper is here: https://iopscience.iop.org/article/10.3847/1538-4357/ab1d52 https://iopscience.iop.org/article/10.3847/1538-4357/ab1d52 phys.org: just say no.
- justfor1comment 7y agoI don't know why an organization called phys.org might need such sensationalization of mundane news. Every article including this one makes it sound like new developments have occurred in physics. When you actually read the article and apply a small helping of skepticism you realize, the world is just the way it was yesterday. phys.org is not HN worthy imho.
- pergadad 7y agoWell they too need clicks. Set the right inventive (people more likely click bait links than more sound/dry ones) and it will either go that way or lose out to another org that does. It's like sitcoms with laugh tracks. Everyone you ask hates them, but if you ask people how much they enjoyed/would rewatch/would recommend/... a certain show they consistently give higher ratings to an episode with vs without canned or study laughter.
- gjm11 7y agoIn fairness, all the sensationalization is in the original press release put out by UC Riverside; phys.org has just copied that wholesale (which is what they generally do).
- papito 7y agoMost of the Universe is uninhabitable. People keep talking about the "Goldilocks Zone" but that is just one factor. * We are on the outskirts of the Milky Way because the center of the galaxy is radiation hell. A chunk of most galaxies is too "hot" for life. So take most of the SPACE out there and move that to the side. * The planet itself has to be around a star that's not too big and not too dim, at the right distance, of course. * Our Solar system is very special as it has the planets in stable, almost circular orbits around a SINGLE star. It's not "collision central", where most planets can still smash into each other, within a binary star system, to boot. * We have gas giants, by chance, protecting us against space rocks flying into us. * The Moon, just the right size, just the right distance, to keep us in stable rotation, with seasons. * Just the right amount of water. Too much or too little water, and we would not be here. * I am probably missing a bunch... * And only then you get to the rest of the factors for life to be possible.
- cheschire 7y agoAnd timing! With humans only being 150,000 to 200,000 years old, and really only intelligently processing input from the stars for less than a century, we're basically talking about two people trying to wave at each other from airplanes that aren't even flying over the same country.
- jacquesm 7y agoIsn't Homo Sapiens > 300K years old? Not to detract from your wider point which is completely valid.
- cheschire 7y agoIt's a spectrum, really. Homo sapiens are generally about that old, but when you start talking modern anatomy, behaviors, etc, what we would recognize as "human" is much more limited. If anything, what you bring up kind of goes right along with my point! There may be life out there, but what is life, or intelligent life for that matter? How would we know what we were looking at if we even saw it?
- lngnmn1 7y agoProbably somebody already thought this, but it seems that life could never escape its original planet - it always self-destruct itself like a too-successful virus which kills its host too quickly.
- YeGoblynQueenne 7y agoThis is extremely human- and Earth- centric. It's as if the only life we're interested in finding in the universe -the entire universe- is life identical to life on Earth. Life that needs an environment just like Earth, and can't survive in any environment that is not like Earth. Life that even has hemoglobin! How likely is it that all life in the universe must be like life on Earth? Actually, by the study reported in the above article- very unlikely. Anyway, I'm reminded by this quote by Douglas Adams (veers off to something else entirely but it starts very relevant): Imagine a puddle waking up one morning and thinking, "This is an interesting world I find myself in — an interesting hole I find myself in — fits me rather neatly, doesn't it? In fact it fits me staggeringly well, may have been made to have me in it!" This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it's still frantically hanging on to the notion that everything's going to be alright, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for. We all know that at some point in the future the Universe will come to an end and at some other point, considerably in advance from that but still not immediately pressing, the sun will explode. We feel there's plenty of time to worry about that, but on the other hand that's a very dangerous thing to say. https://en.wikiquote.org/wiki/Douglas_Adams https://en.wikiquote.org/wiki/Douglas_Adams