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James Webb Telescope Confirms That the Universe Is Expanding at Different Speeds
- nabla9 2y agoThis result has 8.3-sigma confidence, so it's as good as it can get statistically. Even greater confidence than that of the Hubble tension itself. The Hubble Tension is real. The expansion of universe is accelerating.
- wrycoder 2y agoThey confirmed[0] that the Hubble Tension[1] is a valid discrepancy between the two different ways of measuring the expansion of the universe. [0] https://iopscience.iop.org/article/10.3847/2041-8213/ad1ddd https://iopscience.iop.org/article/10.3847/2041-8213/ad1ddd [1] https://en.wikipedia.org/wiki/Hubble%27s_law#Hubble_tension https://en.wikipedia.org/wiki/Hubble%27s_law#Hubble_tension
- nabla9 2y agoTwo different ways in two different times in the lifetime of the universe. expansion rate in the early universe << expansion expansion rate. -> accelerated expansion .
- layer8 2y agoNo. The fact that the expansion is accelerating was already established by supernovae measurements alone [0]. The Hubble tension is about the degree of acceleration, not about whether there is an acceleration or not. [0] https://en.wikipedia.org/wiki/Accelerating_expansion_of_the_universe https://en.wikipedia.org/wiki/Accelerating_expansion_of_the_...
- mr_mitm 2y ago> The expansion of universe is accelerating. We knew that before. This goes deeper than that. It accelerates in a way that cannot be explained by a constant dark energy density, which is part of our standard model. We have plenty of alternative models that can explain this, but our measurements are not precise enough yet to rule any of them out. Hopefully Euclid will provide data that is.
- peppertree 2y agoI can explain it with higher dimensional turbulence. Where is my Nobel.
- rrix2 2y agoIt's in a box wrapped up in your peer-reviewed scientific papers
- throwway120385 2y agoYou'll have to perform some experiment to earn that, sorry. Not even Einstein could win a Nobel just by having a good idea.
- echelon 2y ago> We knew that before. There was an amazing paper on this published on HN a year or three ago that explained at certain discrete points in the future, entire percentages of the known universe will be beyond our reach. It was profoundly beautiful and sad at the same time. I'll try to dig it up. Edit: found the post (three years ago) and some of the quotes and figures I pulled from it: https://news.ycombinator.com/item?id=26734913 https://news.ycombinator.com/item?id=26734913 Edit 2: another commenter had made a note about the Big Rip. I was writing a response, but they unfortunately deleted their (good) comment. I'll include my response below: > wait until you find out about the Big Rip (paraphrasing) That one's even wilder. To think every atom of every place and loved one you ever touched would vanish infinitely far away. Every atom and then subatomic particle of your own once corporal body, regardless of its final resting place, torn and scattered. Last Contact is a great short story if you're in the mood [1]. Then there's vacuum collapse and all the other theories. I wonder what humans or human descendents 500 years from now will figure out about the universe's ultimate fate. [1] https://zestfullyblog.blogspot.com/2011/02/last-contact-by-stephen-baxter-part-1.html?m=1 https://zestfullyblog.blogspot.com/2011/02/last-contact-by-s...
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- dracovolans 2y agoThis does not seem strange to me, since time does not flow the same everywhere - and phenomena occur at different subjective speeds.
- spenczar5 2y agoI don’t understand what “time does not flow the same everywhere” means. Can you elaborate?
- NegativeLatency 2y agohttps://en.wikipedia.org/wiki/Time_dilation https://en.wikipedia.org/wiki/Time_dilation
- xyzelement 2y agoI don't want to discourage question-asking but you're now asking someone to give you a background on a physics phenomena without them knowing your starting level. It's awesome that the poster you're replying to introduced a new concept to us (not something I was thinking about, either) and literally taking the thing you quoted: "time does not flow the same everywhere" into Google will give you a starting point for your quest - you'll see even from the blurbs on the search result page that per relativity, time changes depending on where and how fast you're traveling. You can then dive into what that means you want to as well. I good followup could be something like "I read about relativity and I still don't understand the connection you're making to this current article or something like that - but it doesn't seem fair to skip a basic Google search before asking for elaboration.
- spenczar5 2y agoOkay. I am a professional astronomer at the University of Washington, and I don’t see that phrase as holding very much meaning. In particular, “flow” is a messy word to use. A generous reading of the OP might be that it is a restatement of special relativity, but then it is indeed disconnected to this measurement. An uncharitable reading would be that it is spiritual goop. Anyway, I prefer to let someone answer in their own terms.
- olesya1979 2y ago[dead]
- cl42 2y agoCan someone more familiar with the science help me out? - On the one hand, the universe can be expanding at different rates. - On the other hand, is it possible our approach to measuring the expansion (e.g., using Cepheid variable stars) might be the problem?
- spenczar5 2y agoWe don’t really know - you are right to ask this question. There are two methods and they disagree with each other. JWST is precise enough to rule out a simple reason like instrument imprecision. So remaining possibilities are new physics, a deep flaw in our assumptions/methods, or a universe which is not uniform (but in a peculiar way).
- rainbowzootsuit 2y agoPerhaps the small anisotropy that is observed in cosmic microwave background observations imprints to the dark energy that accelerates expansion. I haven't kept up on the modern state of the art.
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- wuliwong 2y agoI've found this interesting and have read up a little on it. I believe there have been a good amount of studies trying to verify the different measurement methods. I believe they have made some progress in verifying the methods but I'm sure there is still more work to do. I think this is mainly in attempts to deal with the "cosmological crisis."
- magicalhippo 2y agoBecky Smethurst, an astrophysicist, goes through how the cosmic distance ladder works and the recent JWST results here[1]. As you say, measurement errors of Cepheid stars has been something scientists considered a possibility, hence why they're cross-checking by measuring them in different ways. And, as mentioned in the posted article and the other papers mentioned in the video, it seems that measurement errors are very unlikely to be the culprit. Preprints to the articles Becky mentions are here[2][3][4]. [1]: https://www.youtube.com/watch?v=3NeKR7bqolY&t=1330s https://www.youtube.com/watch?v=3NeKR7bqolY&t=1330s [2]: https://arxiv.org/abs/2401.04773 https://arxiv.org/abs/2401.04773 [3]: https://arxiv.org/abs/2401.04776 https://arxiv.org/abs/2401.04776 [4]: https://arxiv.org/abs/2401.04777 https://arxiv.org/abs/2401.04777
- dataflow 2y agoConfused, are they saying that different parts of the universe are expanding at different rates? Or are they saying two methods give different results for the same parts?
- 1053r 2y agoThe second one. This result confirms that the "hubble tension" is real. In other words, two methods for measuring the expansion of the universe disagree, but we can't figure out why and have new and really strong evidence that the "cosmic ladder" method is correct. (The other method is based on the cosmic microwave background radiation and our best theories of physics, so we're caught between a rock and a hard place here: strong experimental evidence one way, and throwing out a ton of what we think we know about the universe with no obvious replacement the other way.)
- TheBlight 2y agoIs this a discrepancy a MOND variant could account for?
- SAI_Peregrinus 2y agoTwo different methods give different results for the same parts. Very poorly phrased article.
- another_poster 2y agoInteresting, could a physical system exploit differences in the rate of expansion? What happens to an object as it moves from a high rate-of-expansion region to a low rate-of-expansion region?
- cwmma 2y agothe current thought is that these are measurement errors not actual differences in expansion rate but even if they were actual different expansion rates, they are separated by time not space.
- m3kw9 2y agoSo it means it isn’t expanding like a sphere but like an irregular explosion?
- 1053r 2y agoNo. This confirms that the "hubble tension" is real. In other words, two methods for measuring the expansion of the universe disagree, but we can't figure out why and have new and really strong evidence that the "cosmic ladder" method is correct. (The other method is based on the cosmic microwave background radiation and our best theories of physics, so we're caught between a rock and a hard place here: strong experimental evidence one way, and throwing out a ton of what we think we know about the universe with no obvious replacement the other way.)
- gagaJo 2y agoCosmology feels a lot like quackery these days. Does it even bother to rely on physics? Physical experiments show explosions do not propel all matter at the same rate. James Webb telescope recently found galaxies that were “too old”, would have formed right after the Big Bang. The prevailing wisdom was all matter spread out evenly due to the Big Bang, then coalesced into galaxies (I emailed various researchers to confirm I understood this was indeed the consensus). But again, other physics shows that clusters of matter ejected from explosions are never uniformly distributed. Just more evidence the well educated (I assume if it’s concensus driven even the best educated agree) are just typical people and their expertise should be challenged constantly rather than sit back and assume things are figured out. As Asimov illustrated in the Foundation, if you aren’t measuring for yourself you’re serving someone else’s interpretation. Hyper-normalized social society just leads to normalization of outputs, which helps preserve and propagate poor science.
- addaon 2y ago> explosions… explosions What are you drawing an analogy to explosions with in this comment? The Big Bang? Why do you expect the analogy to be as precise as you seem to take it to be?
- gagaJo 2y agoBecause researchers put on emotional costumes to serve how they pay for food and shelter, spend their time defending crap results for years/decades. Let’s not pretend the replication crisis isn’t real and endemic within academia these days.
- michaelmrose 2y agoCan you kindly boot up a few more universes so we can do replication properly. Also set the speed to 10,000,000,000x I don't have all year.
- 1053r 2y agoWe have some pretty good ideas about just how "lumpy" the explosion of the big bang should have been. And yes, the best theories in cosmology disagree with the recent observations highlighted in this article. On the other hand, those cosmological theories are rooted in extremely strong physics which does things like predict various attributes of particles that have been measured extremely precisely and were predicted correctly. So the Hubble tension is real. My money is on the theory needing revising, but how? There are no great candidates for something to replace the standard model and our best theories in cosmology. There are plenty of candidates, but no obvious methods to choose a best one. This is science! Remember, the most exciting words in science are, "huh, that's odd." The Hubble tension is extremely odd!
- digging 2y agoThis is a poorly written article, it almost appears whole paragraphs are missing. For instance the phrase "an impossibly high value when compared to Planck’s measurements" is not explained at all. (Planck was a physicist, but I suspect they're referring to https://en.wikipedia.org/wiki/Planck_(spacecraft) https://en.wikipedia.org/wiki/Planck_(spacecraft) I think what it's actually saying is that we've confirmed that the Hubble tension is real. Whether or not that means different parts of the universe are accelerating at different speeds is still not clear. If the meaning of the results is deeper than that, it seems to have completely eluded the author who nonetheless wrote a breathless exaggeration of the findings. EDIT: In 2024 actually I have to wonder if any humans were involved in the making of this article. It certainly doesn't appear to have passed an editor's eyes.
- usernamed7 2y agogiven everything we already know about the fabric of spacetime, this makes sense. Every time we expect there to be an even distribution, we find more structure. So if something like dark energy is the driver of the expansion, and there is an unequal distribution of that, then this would be an expected outcome. But of course, without this new data it would be difficult to believe!
- escapecharacter 2y agothis is because when we looking closely at the game bounds, God gets nervous and throws in some Perlin noise to keep us guessing
- m3kw9 2y agoI thought universe is infinitely large, how is it expanding
- nabla9 2y agoInfinite can expand.
- m3kw9 2y agoIf so it can also contract to become zero?
- notaustinpowers 2y agoFrom my understanding, The infinitely large theory relies on the Universe being incredibly complex in terms of dimensions. The best way to describe it is like a balloon Take a deflated balloon and draw two dots next to each other on it. Then blow up the balloon. The dots are further away from each other (universe expansion). And if you "walk" across the balloon, you can make a full circumference so you never run into an edge (infinite).
- Aachen 2y agoIt's not that there is a shifting boundary where the universe ends, but what is meant with universe expansion is (per my understanding) that objects grow further apart over time without experiencing acceleration or any force acting upon them. It's like drawing a map on grid paper and then increasing the grid size without adjusting the scale: all distances become larger This stretching includes any photons traveling across the grid, and the stretching causes them to expand. Longer wavelengths are more red, giving us the word redshift for stretched light rays. That's one of the ways we measure the expansion: see how much redder the light is as you look at more and more distant objects
- epgui 2y agoI'm not sure if we know that the universe is infinitely large. I do know[1] that: - it's larger than we will ever be able to know or observe (ie.: the observable universe is smaller than "all of the universe"... although that feels a bit hand-wavy to say) - it's expanding. --- [1] I am a scientist, but not a physicist. Everything I said could be wrong.
- foobarian 2y agoI get that the universe can be expanding, and that there might be different methods to calculate/measure this that have discrepancies. But that the rate of expansion is accelerating, how in the world is that possible?
- epgui 2y agoWhat makes you think that should not be possible? It's a pretty well accepted fact.
- spenczar5 2y agoI think it is fair to find dark energy disturbing! It disturbs many cosmologists. It is very established empirically but we lack a good explanation.
- xandrius 2y agoAs far as I understand dark energy/matter is not established, it's just a placeholder as we don't quite know what's missing in our formulas. Isn't it like that?
- foobarian 2y agoI don't think it's not possible, I just find it surprising based on the layman understanding that gravity is a dominant force at long distances, leading me to believe that expansion should be slowing. I also have the layman awareness of some kind of missing mass sometimes explained by "dark matter." But I did not see the additional explanation that this "dark matter" also acts as a repulsive force to accelerate the expansion. Maybe large scale structures manage to create propulsive forces that happen to point away from the center? Anyhow I would love to know what the mechanism is there.
- datavirtue 2y agoYou should ask how fast the expansion is.
- macleginn 2y agoDoesn't this article talk about the same problems and results? https://science.nasa.gov/missions/webb/nasas-webb-hubble-telescopes-affirm-universes-expansion-rate-puzzle-persists/ https://science.nasa.gov/missions/webb/nasas-webb-hubble-tel...
- layer8 2y agoPrevious discussion (363 comments) linking to a better article: https://news.ycombinator.com/item?id=39673087 https://news.ycombinator.com/item?id=39673087
- Temporary_31337 2y agoJust as the Three Body Problem releases on Netflix and science starts to break down? ;)
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- kjkjadksj 2y agoIf the universe expands at different speeds, is it even possible to determine expansion relative to earth since you don’t have something fixed (since everything is at different speeds) to measure earths local expansion against?
- malfist 2y agoYes, in fact, because the big bang happened everywhere and not in one central place, pretty much every part of space is moving away from Earth, so movement from earth is a pretty good measurement. Think of it not as things moving apart, but that space, emptiness, is expanding. Like if you laid the universe out on a sheet of rubber and then pulled at the corners. Everything gets further apart and the expansion is happening everywhere
- bashinator 2y agoGarbage article, clickbait tile; they're talking about the Hubble tension, not any kind of anisotropy in the Hubble constant. The latter would be actual news.
- wutwutwat 2y agoBut what is it expanding into? If the universe is expanding like a balloon then there's some sort of "edge". What is that edge expanding into? Imagine we had a craft that could take us to the edge and you could stand on it, the way you place your finger on the outside of a balloon. If you could stand on the outside/edge of the expanding universe, what would you see, that we're expanding into? It can't be nothing. Something can't expand into nothing.
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- windsurfer 2y agoThe edge of the Mandelbrot set expands out to infinity and yet the area within the edge is finite. Who is to say that the universe isn't a hologram on a higher-dimensional Mandelbrot set-like object?
- Night_Thastus 2y agoI don't agree. You're assuming that the universe is a distinct 'something' expanding into a distinct 'nothing'. I disagree, I think that the 'universe' is an arbitrary border we created. If we were somehow able to accelerate a particle out past the edge of the known universe, now the bubble includes that particle too and essentially we've 'expanded' the universe. In other words, the arbitrary bubble containing things that we know about and consider significant is larger than it was before - because there's something out there we can observe.
- wutwutwat 2y ago> I think that the 'universe' is an arbitrary border I don't think that the scientific definition of the universe matches this. It's a physical thing, not a construct we made up. It's not an imaginary line between two countries. The universe is full of things which have mass. Those things are rapidly expanding outward. What are those masses expanding into as they "blow up the ballon" and push the boundaries of the universe outward? It can't be nothing, it's physically impossible. EDIT: might as well quote people smarter than I > The universe is all of space and time[a] and their contents.[10] It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of energy and matter, and the structures they form, from sub-atomic particles to entire galaxies. Space and time, according to the prevailing cosmological theory of the Big Bang, emerged together 13.787±0.020 billion years ago,[11] and the universe has been expanding ever since. Today the universe has expanded into an age and size that is physically only in parts observable as the observable universe, which is approximately 93 billion light-years in diameter at the present day, while the spatial size, if any, of the entire universe is unknown. https://en.wikipedia.org/wiki/Universe https://en.wikipedia.org/wiki/Universe
- starfancier 2y agoThe "cosmic ladder" supposition's underpinnings are a bit shaky anyway. Calculating distance and age by examining ever distant Cepheid variable stars is prone to cumulative error. But it's the best estimate we've got.
- pmayrgundter 2y agoThe [Study] has a better framing in its title "JWST Observations Reject Unrecognized Crowding of Cepheid Photometry as an Explanation for the Hubble Tension at 8σ Confidence". It rejects the hypothesis that there was a systematic observational problem in observing Cepheid variables (CVs), which are in turn used to estimate distances to Type Ia Supernova (SNs), towards a long-term goal the Study concludes with of "Tying all of these together by observing large samples in common can lead to the calibration of ∼100 [SNs] and a <1% local measurement of [The Hubble Constant, H0], a landmark in our quest to understand the expansion of the Universe." Notably the paper doesn't provide a new estimate of H0, but it does strengthen the case for CV/SN being at odds with other methods of estimating H0, a problem called the Hubble Tension. JWST was built primarily to extend the sensitivity range for infrared observations, so we can see fainter sources from further away, or near sources with greater resolution. This study is about the latter.. the study of CVs and SNs in nearby galaxies. "the significantly greater resolution of JWST over [Hubble Space Telescope] has greatly reduced—in practical terms, almost eliminated—the main source of noise in [Near-Infrared] photometry of [CVs] observed in the hosts of nearby [SNs]. The resolution of JWST provides the ability to cleanly separate these vital standard candles from surrounding photometric "chaff." CVs and SNs are "standard candles", rungs on the Cosmic Distance Ladder[CDL], the framework we use to compare and contrast different astronomical distance measurements. The term "standard candle" is used for a physical process we think we understand well enough to use its appearance at astronomical distance to infer other properties of its observation, e.g. the candle's color shift towards red the further away it appears to be. ("appears" since we can't directly measure actual distances, but observe that galaxies get smaller/fainter/redder together) Cepheids are a relatively common kind of star that pulsates regularly during its lifetime, while SuperNovas are much rarer one-time very bright events. SNs are really useful to see them far away bc how bright they are, but since there's so few of them, we calibrate nearby SN distances based on the many CVs in the host galaxy of the SN. In all, this study starts by looking at CVs in NGC 4258 at 23 Million lightyears away, and then looks for photometric crowding of CVs at successively further steps away in NGC 5643 (41 Mly), NGC 1559 (48 Mly), NGC (1448 56 Mly) and NGC 5468 (140 Mly), but don't find evidence of crowding to account for apparent brightness/closeness of the CVs, so rejects that idea with a high confidence. Those galaxies are actually as far away as they appear to be if CVs are good standard candles. These are at the nearer end of the CDL.. 140 Mly vs the observable Universe is thought to be at least 13 billion light years radius. But if it in turn makes us more confident about SNs, those go out to a current max of 16Bly[FarthestSN]. [Study] https://iopscience.iop.org/article/10.3847/2041-8213/ad1ddd https://iopscience.iop.org/article/10.3847/2041-8213/ad1ddd [CDL] https://en.wikipedia.org/wiki/Cosmic_distance_ladder https://en.wikipedia.org/wiki/Cosmic_distance_ladder [HT] https://xkcd.com/2516/ https://xkcd.com/2516/ [FarthestSN] https://en.wikipedia.org/wiki/SN_UDS10Wil https://en.wikipedia.org/wiki/SN_UDS10Wil