10 ms·
Asymmetry detected in the distribution of galaxies
- thunkle 4y agoHow do they know the galaxies are connected?
- niccl 4y agoAs I understood the article, they made no assumptions abut connectedness. They basically tried all combinations of 4 galaxies out of their sample set, and counted the handedness of all those. some clever maths required to deal with the combinatorial explosion
- addaon 4y agoYep. The key here is that if you choose four arbitrary galaxies from a set, there's two possibilities -- their positions in space are close enough that there's interesting things to be learned about their formation; or they're not. In the latter case, there's a strong reason to expect no bias to the tetrahedral side lengths; in the former case, there may or may not be. If you then look at all possible combinations of four galaxies -- including all the four-tuples that are "real" in 3D space, but also all the four-tuples that aren't -- the average of "no bias" and "interesting bias" will be "smaller, but interesting bias." Which is why, once a bias is found, figuring out it's p value is non-trivial...
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- borbulon 4y agoI wonder how long it took the computer(s?) to run the permutations
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- hossbeast 4y agoIsn't 1M galaxies just a drop in the bucket?
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- routerl 4y agoIs a million dollars the same as zero dollars, to a billionaire?
- sph 4y agoThe universe is almost a trillionaire (in estimated number of galaxies). So it would be like $1 to a millionaire or 1 cent to an average lower class family: inconsequential spare change
- nyani 4y agoEvery dollar greater than a dollar was as a dollar. Every penny greater than a penny was a penny. Every human greater than a human was a human. All that to say everything came from somewhere; consequentiality is another matter.
- qzw 4y agoYes, and apparently there are plans to do the same analysis on a newer sky survey that will have around 30M galaxies, which is ... also a drop in the bucket if we're talking hundreds of billions of galaxies in the observable universe. But if the same result holds, then it would definitely offer stronger evidence, particularly if the surveys are of very different regions of the universe, because some studies have suggested that the laws of physics may not be quite the same throughout the universe.
- tintor 4y agoDoes anyone know what coordinate system would be used for something like this?
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- Waterluvian 4y agoI think they avoided the problem by working with topology? But I barely understand this article.
- hnau 4y agoright ascension and declination, i.e. equatorial coordinate system
- qzw 4y agoI guess it would be one of these: https://en.wikipedia.org/wiki/Astronomical_coordinate_systems https://en.wikipedia.org/wiki/Astronomical_coordinate_system... But I think for this study it doesn't really matter. As long as all the galaxies are in the same coordinate system, they can calculate the relative distances between any two galaxies. And since they all came from the same sky survey, all the data was probably already in the same coordinate system.
- spog314 4y ago
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- sockaddr 4y agoThey realized it? Or merely claimed it? I did a quick google search that didn’t turn up anything obvious. Got a source?
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- 9wzYQbTYsAIc 4y agoI believe that this is the research being described in the article: https://arxiv.org/abs/2206.03625 https://arxiv.org/abs/2206.03625
- Sniffnoy 4y agoThat and https://arxiv.org/abs/2206.04227 https://arxiv.org/abs/2206.04227 ; the article links to both of them early on, but it is perhaps easy to miss.
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- quadcore 4y agofrom a catalog of 1 million galaxies For a lay person, reading that number is mind blowing. Quick question: how many do we think there are? Or rather, do we have some sort of a number for the total energy there is in the universe compared to that of our sun?
- hnuser123456 4y agoAbout as many galaxies in the universe as there are stars in the galaxy: hundreds of billions, ~10^11
- Buttons840 4y agoThat's a neat symmetry. Another symmetry I like, in the other direction, is a fist is to the Earth as a carbon molecule is to a fist sized rock (I might be off by a magnitude or two, but by charitable interpretation it's accurate enough). That's a lot of molecules.
- routerl 4y agoEstimates place the number of galaxies at around 200 billion, give or take an order of magnitude. The total energy produced by our sun during its entire lifetime is insignificantly miniscule compared to all the energy emitted by every star in the universe for a single nanosecond.
- 9wzYQbTYsAIc 4y agoSimilar in scale the number of neurons in a brain: 86 billion neurons [1]. One neuron might seem insignificantly miniscule, but just one neuron may encapsulate you recognizing a specific face of someone important to you. [1] https://bionumbers.hms.harvard.edu/bionumber.aspx?id=106322 https://bionumbers.hms.harvard.edu/bionumber.aspx?id=106322
- nr2x 4y ago...and yet I remain very bad at putting names on faces.
- EMM_386 4y agoGiven the Gosmic Microwave Background Radiation, and things like this study, there were clearly some "parameters" in effect at the strart of the universe. I'll stop there, call that whatever you want. But whatever those parameters were, allowed me to type this comment on Hacker News.
- paulrouget 4y agoCould that arise from any early parity symmetry breaking of the weak force? If anyone is interested in parity symmetry or CPT symmetry in general, I can't recommend this book enough: https://en.wikipedia.org/wiki/The_Ambidextrous_Universe https://en.wikipedia.org/wiki/The_Ambidextrous_Universe and in particular the part about the Ozma Problem: https://en.wikipedia.org/wiki/The_Ambidextrous_Universe#The_Ozma_Problem https://en.wikipedia.org/wiki/The_Ambidextrous_Universe#The_... Fascinating stuff.
- loxias 4y ago> Could that arise from any early parity symmetry breaking of the weak force? This is the first thing I wondered! I'm not a physicist and don't know how to answer the question usefully, but if you ever find out, please reply to the thread and let me know. I'll do the same. :)
- infradig 4y agoThe question is asked and answered in the article. No.
- scotty79 4y agoI think it could be interesting to measure this assymetry in different parts of the sky and make a sort of map of it. Maybe the cosmos has sides?
- ggm 4y agoThe question might be, if you ran the experiment again, would you get the same bias, or a different one? (as in, go back to the gnab gib and .. do over)
- nr2x 4y agoI also like the simulation hypothesis. :-)
- ggm 4y agoI get angry when people use it to justify "all moral rules are silly we're just a simulation" -if its a good simulation, then social precepts have value, irrespective. Except for the ones I don't like of course, they're going in the v0.2 iteration..
- psychphysic 4y agoIt sounds as though the experiment calculated all possible tetrahedra with the dataset. The null distribution was found by randomly generating similar datasets (monte carlo). So it seems like you'd get the same result each time. The calculation sounds stupendously complicated. I can't wait to see it in next year's advent of code with some dbag claiming a sub-seconds run time.
- est31 4y agoThey have encountered an interesting algorithmic problem here, very cool. To determine whether the universe as a whole has a preferred handedness, they had to repeat the analysis for all tetrahedra constructed from their database of 1 million galaxies. There are nearly 1 trillion trillion such tetrahedra — an intractable list to handle one at a time. But a factoring trick developed in earlier work on a different problem allowed the researchers to look at the parity of tetrahedra more holistically: Rather than assembling one tetrahedron at a time and determining its parity, they could take each galaxy in turn and group all other galaxies according to their distances from that galaxy, creating layers like the layers of an onion. The linked earlier work: https://academic.oup.com/mnras/article/454/4/4142/993302 https://academic.oup.com/mnras/article/454/4/4142/993302
- vlovich123 4y agoGiven there’s 100 billion-1 trillion galaxies estimated in the observable universe, isn’t 1 million a frighteningly small sample to draw conclusions from? How can we be sure that what we’ve observed is representative enough to extrapolate conclusions of? Moreover, how do we know if extrapolates to the universe homogeneously? What if the “opposite” asymmetry is present in the non observable universe such that on average the universe doesn’t actually have an asymmetry globally?
- nr2x 4y agoI'm guessing they thought of that.
- kaashif 4y agoSuch an incredibly large scale asymmetry would still be interesting even if it weren't global for some reason. Even if there's a sampling thing going on, why should this particular sampling method have an asymmetry? Maybe there's no reason, or maybe there is a reason.
- graycat 4y ago> ... a frighteningly small sample to draw conclusions from? Just make the usual assumption: The data consists of random variables that are independent and have the same distribution. Or "independent and identically distributed", i.e., the i.i.d. case. Then can apply the theorems called the law of large numbers, either the weak version or the strong version. Then in the application of the law of large numbers, the number of samples is crucial, but, possibly surprisingly, the number of cases in all the data does not get involved, is not used in the law of large numbers, and is irrelevant. That is, to be more explicit, with this approach, we don't care how many galaxies there are, 10^12, 10^100, 10^1000, whatever. Right: With different approaches, might care a lot about (a) the number of galaxies there were in total, (b) the number of galaxies used in the analysis, i.e., if in (b) we had enough samples to characterize (a), to have a good approximation of the results we would get if we analyzed all of (a). For more, might claim that (A) the distribution we use in the law of large number is just that of ALL of the galaxies, a large number but not infinite (commonly a distribution is for infinitely many) and (B) drew the sample to be analyzed by rolling dice or some other mechanism that achieved independence so that, net, we have i.i.d. as wanted for the law of large numbers. So, here the distribution is not of some imaginary collection of infinitely many galaxies but just of the large but finitely many galaxies there are in THIS universe or THIS observable universe, or ..., this universe once we get tired of collecting data, start to run out of grant money, want to get home with the kids, want to watch the soccer matches, ...!
- Lucent 4y agoOddly no mention of two-point correlation, another anomaly suggesting quantum effects at the birth of the universe gave it its large-scale structure. https://en.wikipedia.org/wiki/Correlation_function_(astronomy) https://en.wikipedia.org/wiki/Correlation_function_(astronom...
- nighthawk454 4y agoThat's really interesting, thanks! Is it that if the early universe was initially even slightly non-uniform, then expansion and gravity would persist those "imperfections", forming the galaxy clumps we observe now?
- usgroup 4y agoI don’t think clumsiness is related. That galaxies favourably exist along gas filaments is not you .
- amai 4y agoThe tetraeders they are talking about in the article are a different name for 4-point correlation functions. The papers headline only mention 4-point correlation function, but the journalist must have decided, that this term is too technical for a pop-science article.
- pleb_nz 4y agoSo what did this mean in layman
- bowsamic 4y agoI'm a physicist but this isn't my field, so I will comment with my understanding, which may be wrong. Usually we expect that on a large scale there should be a uniform structure across the universe, i.e. the universe should be homogenous on a cosmic scale. Galaxies should be for the most part evenly distributed across the universe since everything came from a singularity at the big bang. The reason why we see any asymmetry on a small scale, e.g. we see galaxies and stars and planets form, is because of comparatively "microscopic" effects of physical laws. E.g. clusters, galaxies, stars, and planets form because they overcome the expansion of the universe, but generally the matter should be distributed evenly on a big enough scale. This result is very interesting, because it implies some kind of asymmetric structure of the universe on a huge, cosmological scale. But how can such a structure arise? What causes such a structure to arise?
- fdvbvvgh 4y agoHttp://fac.com/arc
- lamontcg 4y ago> “If this result is real, someone’s going to get a Nobel Prize,” I hope it is real, the result sounds legitimately very exciting. Hopefully they manage to measure the same parity violation in the CMBR.
- jhoechtl 4y agoI hear topics of analysis of distribution of galaxies from time to time and always wonder how we can actually measure this distribution in any sensible way? What I mean is: Information reaches us at max the speed of light. Information about galaxies from millions of light years afar contribute to the distribution model. Thus the model incorporates spatial distributions of objects (=galaxies) which are certainly no longer true as of now. Put differently: When we assume the big bang and assume further as a thought experiment that mass expands equally, the model would requires to account for information from early objects, where mass distribution was different. Otherwise the conclusion would be drawn that mass is unevenly distributed.
- torotonnato 4y agoDisclaimer: absolutely not an expert. As I understood it, this is a test for the cosmological principle, which should be valid for every observer at every point of spacetime
- zaphirplane 4y agoGalactic scale warfare or galactic scale energy harvesting ? :)
- 867-5309 4y agochaos was the law of nature; order was the dream of man
- psychoslave 4y agoThe man was just a byproduct of nature, as well as its dreams. Ergo chaos is mother of order.
- 867-5309 4y ago*the dream of order
- yunruse 4y agoLife can benefit from and seek low-entropy solutions - they are easier to deal with for many situations, be they cognitive, evolutionary, or otherwise. But in the process of making them we naturally put the second law of thermodynamics to use, i.e. increasing entropy in the universe around us. It is vaguely reminiscent of a heat engine - we do our best to expel entropy, but in doing so create slightly more. Therefore (to put it poetically) it could be argued that chaos creates order to beget more chaos, just like a refrigerator does work to inevitably increases the net heat around it. This is reminiscent of the saying "a foolish consistency is the hobgoblin of little minds" - it is strategically better to embrace a little chaos in the details that do not overly matter, to focus on consistency where it actually benefits.
- account-5 4y agoCan someone EIL5 as to the significance of this? How does drawing lines between galaxies show asymmetry. Why is that important?
- Rwdaunch 4y ago
- rafabulsing 4y ago> How does drawing lines between galaxies show asymmetry You know how there's no way to rotate your left hand to make it look like a right hand? There's always something different. The palm facing the opposite direction, or the thumb is at the other side. The same can be done with tetrahedrons. If they have all different length sides, you can find that the ordering of the sides from shortest to longest go on "spin" around one of the vertices, in a way that doesn't change no matter how you rotate the shape. The way we understand the universe, we expect that we would have 50% of such arrangements "spinning in one direction", and the rest to "spin in the other direction". But it's actually not balanced. > Why is that important? If the result is confirmed, it's important because it breaks one of the fundamental assumptions we had about the universe. We don't know what would cause this difference yet, but the finding proves that there is/was something that would cause this difference, and it is the first clue towards figuring out what it could be.
- enriquto 4y agoI don't understand why do they need this complicated algorithm. If there is such a blatant bias then it can be detected by sampling a few million random tetrahedra; and that can be done instantaneously. Also, why don't they publish the list of positions of all these galaxies? (Or I couldn't find it easily on either of the original articles [0,1]). If there's just a million of them, this is around the same size as a single high-resolution color image. Then people can download the positions and find the asymmetries themselves! [0] https://arxiv.org/abs/2206.04227 https://arxiv.org/abs/2206.04227 [1] https://arxiv.org/abs/2206.03625 https://arxiv.org/abs/2206.03625 EDIT: actually, the data is public and easily available! Here is a notebook for playing with it: https://nbodykit.readthedocs.io/en/latest/cookbook/boss-dr12-data.html https://nbodykit.readthedocs.io/en/latest/cookbook/boss-dr12...
- icare_1er 4y agoI have always wondered how an initial singularity could generate something that is not symmetrical ?
- phlipski 4y agoSounds to me like there's a disturbance in the force...
- WaitWaitWha 4y agoCan someone give me a lycée dropout level explanation what they are writing here? I am gathering that galaxies are spaced in tetrahedral formation, and some fashion there are "mirrors" i.e, tetrahedral formation but with opposite side-lengths, but now discovered that is not so? I am confuserated.
- lostmsu 4y agoHow certain are they, that the source data is not biased due to our own galaxy rotation?
- pmayrgundter 4y agoLarge-scale anisometry can also be viewed as more evidence towards invalidating of the big bang model. Acknowledging the usual pragmas of "all models are wrong" and science needs something to proceed by, I also find it useful the idea of keeping a tally of how many free parameters need to be added to our cosmology as a measure of its (increasingly poor) fit.