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The Universe Is Expanding Faster Than It Should Be
- ahyes123 5y agohumans and their ignorance never ceases to amaze me
- devenvdev 5y agoWe are having an impostor syndrome as humanity, which is a good thing. There was an obvious security hole sitting for years in the most common library in the most common programming language, and no one noticed... We fly to space and begin to do some mega projects, yet some of the most intelligent people in the world are facepalming themselves on a daily basis... We are not smart enough yet.
- throwaway984393 5y agoStrange title. The universe is expanding exactly as fast as it should be... It's the universe. We just misunderstood the expansion rate.
- notfed 5y agoIt's also only an 8% difference...
- BurningFrog 5y agoWhy is the entire universe speeding away from us? What do they know??
- bmitc 5y ago> than it should be This may be pedantic on my part, but I don't like this framing. It has the implication that our models dictate what happens in the universe and not the other way around. The universe is expanding faster than our models predict or there's something up with our observations or both. Maybe this is what people have in mind, but I think it's a subtle communication difference and can miscommunicate that science is truth, whereas science is the collection and evolution of models and observations describing the reality we experience.
- ncmncm 5y agoNot pedantry. This is a common failing in cosmology.
- imoverclocked 5y agoThis is a common failing everywhere. A friend once told me, “stop shoulding yourself.” Turns out, I should’ve listened.
- simonh 5y agoIt is pedantry. This is just idiomatic human communication and not specific to any single domain. People say thing like this all the time. Saying ‘than it should be’ instead of ‘than we expect’ is everyday English language usage that confuses nobody and complaining about it is entirely performative. You’re technically correct, here have a round of applause, but it contributes nothing. Dealing with smug nitpicking like this that’s completely beside the point is one of the tedious chores or reading HN.
- bmitc 5y agoIt's a problem because it miscommunicates to non-scientists about what science actually is and it causes scientists themselves to be misinformed about what they're really doing. I greatly enjoy science, but you have to admit that there's a problem of scientists being viewed as "elites who think they know everything" that is fueled by journalism and the miscommunication of science. It's alright to critique something to try and improve it, you know? Lastly, it's not really besides the point, as our models and possibly our observations being wrong is entirely the crux of this "problem".
- eecc 5y agoOh please, it’s a headline. The pedantically correct phrasing is right below in the second heading, not buried in a footnote. Have you even glanced at the article?
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- ncmncm 5y agoIssue it a speeding citation, hope it learns from its mistake. This is probably just youthful exuberance. If it's still at it after another 13 billion years, take away its license.
- deleted 5y ago[deleted]
- choeger 5y agoDo you have the universe's home address? Maybe it's still living with its creator?
- ncmncm 5y agoThe amazing thing about the universe's home address is that it is always right here, no matter where here is. The Big Bang happened exactly at the tip of your nose. And mine.
- d--b 5y agoSo our gravitation models weren’t working very well, so we thought maybe dark matter. Then that wasn’t working very well either, so we thought maybe dark energy? And now this is showing a lot of shortcomings too? I know nothing of astro physics, but I find it odd that a majority of astro physicians think of dark energy as a near certainty when all mainstream articles are about contradicting its implications.
- dilyevsky 5y agoExpansion of the universe (dark energy) has nothing to do with the dark mater. At least not according to any models known today. We know galaxies are racing away faster because we can see it (from red shift) so that part is certain. Why they are moving away is not certain hence “dark” energy
- ErikVandeWater 5y agoPeripheral question: Without dark matter, would there be more red shift?
- raattgift 5y agoThis is an excellent question. Light exiting from stars deep in a galaxy (which is in turn deep in a galaxy cluster) is subject to gravitational redshift. The greater the mass of the galaxy and cluster, the greater the redshift. If we add transparent, non-radiating mass to a galaxy and its cluster, the mean redshift of starlight from the galaxy will redshift, and we'll see the result on various absorption and emission lines in the spectrum. Note, we do not need dark matter for this; increasing the central mass of a galaxy cluster will do the trick too. We can do this by adding more stars, or by adding black holes, or by making a central black hole more massive. All of this will cause an increase in gravitational redshift. However, adding more central mass to galaxies will be reflected in the trajectories of clouds of gas and collections of stars within the galaxies; likewise, adding more concentrated mass to a galaxy cluster will alter the trajectory of galaxies within it. In general, these objects will have faster orbits -- fast enough that a non-gravitational redshift will be apparent in the arrangement of spectral lines. (We would also need to figure out how to keep any central masses from being extremely bright anywhere in the electromagnetic spectrum, and how to keep them from eclipsing parts of their home galaxies and clusters that are behind them from our perspective.) If we instead redistribute our increase in galactic mass into a gaseous halo-like structure that extends well beyond the outer stars, we get the increased gravitational redshift without requiring stars and gas to travel faster to avoid falling inwards. The halo still has to be electromagnetically quiet, and non-eclipsing, or we would see it. (This all applies to clusters, too). Stepping away from the "dark matter puzzle" of the spectral lines of molecular and atomic gas clouds in galaxies and clusters of them, we can then look at another aspect of your question. Galaxy clusters, from their point of view, are just floating passively in space. The expansion of the universe follows a model wherein if we treat the astrophysical content of galaxies and clusters as sensitive accelerometers that in aggregate show off the peculiar accelerations experienced by these large scale objects, there is no evidence that these accelerometers should report a non-zero magnitude or point in any particular direction. That is, galaxies and galaxy clusters are themselves in free fall, and we can see this because of lines of evidence including expansion-direction-and-magnitude squashings of https://en.wikipedia.org/wiki/Light_echo https://en.wikipedia.org/wiki/Light_echo lines turn out to be null, likewise there are no radio-loud edge shocks for galaxies that appear to be accelerating away from us, there are no shape distortions of the most highly "accelerated" distant galaxies, and so forth. There is simply a spectral redshift. So, for an isolated galaxy the spectrum it emits depends on a combination of its starshine, any noise from close to its central black hole(s), the noise from any thick gas clouds undergoing gravitational collapse, and the absorption and reemission of diffuse gas clouds heated by these types of emission and absorption-and-reemission sources and the distribution of dark matter within and around the galaxy. The more dark matter, the more redshifted the galaxy's spectral lines will be. Preserving the Copernican Principle, immersing a set of such isolated galaxies into an expanding cosmos leads to the inhabitants of each galaxy observing a cosmological redshift on the gravitatonally-redshifted spectrum emitted by other sufficiently distant galaxies. The gravitational-redshift depends on the mass of the galaxies including their dark matter. The cosmological redshift only depends on a light-travel distance from the galaxy, no matter how light or how massive that galaxy (or its parent cluster) is. Next, if we have an arrangement b-->F-->U, where b is a background galaxy, F is a foreground galaxy, and U is an observer, we will that the light from b is cosmologically redshifted before it interacts with the molecular and atomic gas clouds in F, causing a spreading of absorption and reemission lines rather than a thickening. For the very obvious lines from neutral atomic hydrogen, we see this as the https://en.wikipedia.org/wiki/Lyman-alpha_forest https://en.wikipedia.org/wiki/Lyman-alpha_forest which is an important tool in astrophysics and in checking the soundness of our theory of gravitation. We would get a Lya-forest structure even in the absence of dark matter in b or F or anywhere else; only the fine strucutre would differ. Indeed, we could substitute a diffuse static cloud of atomic hydrogen for F and still see a "forest" structure minus small contributions from the starshine in F and the orbital motions of the gas in F around some central mass. The deep infrared noise from F in that case, however, would not be gravitationally redshifted. Finally the answer to your question: the cosmological redshift does not in general depend on the "late" distribution of dark matter. (Late as in at least millions of years after the hot big bang). But the gravitational redshift on light emitted by stars and galaxies does depend on dark matter and in general the starshine is reddened by it. The reddening is because of the additional mass of the dark-matter-containing structures, and also because the distribution of the dark matter into halos allows for slower orbits of stars and gas clouds, thus suppressing their non-gravitational non-cosmological redshifts. (In an edge-on spiral galaxy without dark matter we would see a greater difference in the blueshift of one extreme tip of the thin disk and the redshift of the opposite extreme tip of the thin disk, compared to the same spiral galaxy with dark matter; the light-and-radio from the central bulge would be less redshifted in the absence of dark matter). So, no, the cosmological redshift does not depend on dark matter. The gravitational redshift on light from galaxies, however, does. So does the non-gravitational, non-cosmological redshift on gas clouds whirling around the edges of rotating (e.g. spiral) galaxies, or rising and sinking on radial orbits within elliptical galaxies.
- ngcc_hk 5y agoFailure is so common in this area that using “should” is a bit odd. The problem today is not like the Mercury minor difference (which in one stage some tried to invent a planet inside Mercury orbit called Vulcan). But we are not of that scale. 90+% things we do not know, we just label them as dark … matters or energy. It looks like we know. The key is the dark part. If you do not know 90+% things out there, there is no way you can think of should. Just say the universe once again serve us a curve ball …
- magicalhippo 5y ago> If you do not know 90+% things out there, there is no way you can think of should. They're just leaving off the implied "according to our models" at the end of the sentence. This is mostly fine, because it's obvious we don't know the true model of the universe, so our expectations are based on our current understanding.
- ngcc_hk 5y agoThe key is just not observation. Theory has a lot of issues. For that problem mentioned in the article see this https://en.wikipedia.org/wiki/Cosmological_constant_problem https://en.wikipedia.org/wiki/Cosmological_constant_problem . As a joke, whilst I agreed hard to deal with matters and energy, but even nothing you can model that is tough. I love cosmology and reading about it. Always exciting. But not because of the human part. More positively as said in the article … a lot to be learnt, just do not use the word should you are ok I am ok.
- NoMAD76 5y agoI have a tiny theory but since I'm not anywhere near this domain it could just look dumb. It implies the existence of a multiverse system, billions of universes like ours, like soap bubbles, all floating around each other. Well, if the gravity (and other forces, matter, energy, etc) works as intended then "objects/forces" closer to the universe edge gets pulled away by "objects/forces" from the other universe.
- me_me_mu_mu 5y agoSame I feel like that is the only way. I can’t wrap my head around the concept of infinity. There has to be a beginning and end. What the heck caused the Big Bang? Why?
- NoMAD76 5y agoThere are things (trivial or not) that we can't know or explain with our limited knowledge. But reality is always beyond our wildest dreams.
- gpderetta 5y agoYou think that there has to be a beginning, yet are looking for something that has caused the big bang. Isn't that inconsistent? Why cant the Big bang be the beginning? Otherwise you might next be looking for what caused whatever caused the big bang
- ErikVandeWater 5y agoThe God's Daddy effect: Keep asking for progressively deeper causes until you find one you like.
- podgaj 5y agoAnd this is why I feel science is a religion, both ask questions which can never be finally resolved by humanity's finite brains.
- TekMol 5y agoCould we say that we simply don't know what is going on in the universe? We (well, Einstein & Co. I was not involved.) made models about how the universe works. Then when looking at the broader scope, we noticed that the models differ from reality. So instead of saying the models are wrong, we invented "dark matter". Some unmeasurable type of matter that is responsible for the difference of how reality behaves in contrast to our models. And then we invented dark energy. Now to make our models "work" we have to assume 85% of the matter in the universe is made of dark matter. And 68% of energy in the universe is made from dark energy. How about just saying that our models do not work on large scales? I have a lot more arguments that prove dark matter is a hoax. Let me write them down in dark text (an unmeasurable form of text). Here we go:
- Frenchgeek 5y agoThe models are correct: We're just living in the wrong universe.
- ErikVandeWater 5y agoIs this a quote? It's a good one!
- shusaku 5y agoSabine Hossenfelder explains: https://youtu.be/GatiekRziok https://youtu.be/GatiekRziok
- devenvdev 5y agoI liked her videos a lot, until this one: https://youtu.be/zpU_e3jh_FY https://youtu.be/zpU_e3jh_FY She should stick to physics, not philosophy. Proving free will with physics is ignorant and arrogant. The hard problem of consciousness is much deeper than "in our models, we see that there is no randomness anywhere, ergo no free will."
- mkl 5y agoDark matter and dark energy are models, "made up" to try and model reality's differences from general relativity. General relativity was "made up" when the Newtonian model was found to differ from reality. The Newtonian model was "made up" to explain the Copernican model, which was "made up" when the Ptolemaic model was found to differ from reality. All models are wrong. Some models are useful. Everyone knows that the models aren't perfectly accurate; that's what models do: model. We literally say "this model is wrong" all the time.
- stareatgoats 5y agoCosmology is not a done science. There are a great number of advances that have answered specific problems regarding the behavior of light and energy, mass and gravity and so forth, but our knowledge is not complete (and will likely never be). Articles like this get traction because the lay person may have believed that the science was more mature than it is. (Some) scientists are also notoriously famous for exaggerating how much science "knows" - Stephen Hawkings claim to the mind of God comes to mind. We need to relieve such scientists of the burden of needing to know it all, and be grateful for all the things still left to discover.
- podgaj 5y ago> Cosmology is not a done science. Cosmology will never be a done science. The universe is infinite but the human mind is finite.
- ewindal 5y agoSo is the set of all positive integers, but there is no unknown number in there, even though we haven’t seen them all.
- mensetmanusman 5y agoThere is though, what’s the prime number after 314159265378979323846264338327950288419716939937510582090494459?
- Blammar 5y agoIt's ....58209_7_494459... I checked against my memorized pi expansion. Oddly enough yours and mine stop at the same place!
- mensetmanusman 5y agoYou only need a hundred digits to know the circumference of the universe within the accuracy of the diameter of hydrogen!
- PicassoCTs 5y agoThe anti-matter mirror universe is contracting ever faster.. /s
- vermilingua 5y agoReading articles like this one always give me spooky vibes. Last Contact by Stephen Baxter [1] is a great way to get those vibes. [1] https://web.archive.org/web/20080725045740/http://www.solarisbooks.com/books/newbookscifi/last-contact.asp https://web.archive.org/web/20080725045740/http://www.solari...
- guerrilla 5y agoWell that was sad. A good metaphor for meditating on the fact that everyone will die too.
- NateEag 5y agoThat's a lovely, heartbreaking story. Thank you for sharing it.
- maze-le 5y agoStephen Baxter is one of my absolute favorites when it comes to SciFi literature. He incorporates hard physics with great storytelling in amazing settings few other authors dare to touch. No one manages to imagine the end of the universe better than he...
- tdfirth 5y agoThis is probably really dumb but I'm interested to hear people's reactions to yet another amateur dark energy theory. Could the observation that the universe is expanding actually be the result of a sort of gravitational lensing and not the result of space expanding or bodies moving through space? My rough line of thinking is: - We believe that gravity has a warping effect on spacetime. - We believe that this warping can distort light. - When we observe light from distant galaxies, it must first exit the gravity well of the source, traverse the universe and then make its way down into our gravity well. - Therefore, the light must have been subject to some distortion. It traversed two regions of 'stretched' space time and so became 'stretched' itself. - This 'stretching' is interpreted as redshift and is indistinguishable from if the light source had just been moving away quickly. Naively, I would have thought this interpretation explains a couple of things quite well: - Light would be redshifted in every direction as every bright and distant source (i.e. galaxies) resides in a large gravity well. - It would explain a lack of redshift in nearby objects as we sit in a broadly similar part of the Milky Way's gravity well. As such the relative lensing effect would not be apparent. Anyway, I obviously have no idea what I'm talking about and someone will have thought of this before - however I'm interested to know why the theory doesn't work. Most likely I don't really understand gravitational lensing and it wouldn't distort the wavelength of light as I suggested. Alternatively, perhaps someone has done the maths and the impact of any such effect does not align with observations. edit: formatting
- sigmoid10 5y agoLight is indeed redshifted as it climbs through a gravitational well, but it is also blueshifted again when it travels down the gravitational well of our own galaxy. For distant galaxies, the total effect is negligible compared to the doppler redshift due to their velocity. Also, when you look in any direction in the sky, the redshift increases with distance, irrespective of galaxy or cluster masses. So the further they are away, the faster they are receding from us. This is also exactly what the Hubble constant measures.
- tdfirth 5y agoCool, thanks for the reply! I hadn't considered the blueshifting part, that makes a lot of sense though. I also hadn't heard of Hubble's constant, which I am now learning about :). Very mysterious indeed.
- mrtri 5y agoso earth is moving with the expanding universe? why I'm not feeling any motion? while earth is spinnging wobbling, tilting, going around the sun at 66600mph.following the sun at 450000mph, following the milkyway at 1.3million mph, following the expanding universe at millions of mph.
- podgaj 5y agoThe arrogance! The universe is not expanding faster than it "should" be! Your math is wrong!
- Quekid5 5y agoIt's a figure of speech. "Should" here is short for "should according to our best theories. Therefore those theories are inaccurate".
- podgaj 5y agoI know it is a figure of speech, but it is quite a convenient one! It implies their math is right and the universe is wrong! Let me fix it: "Scientists models of the expanding universe fail again."
- h2odragon 5y agoOne of the early patch sets had a much higher speed of light; but it was eventually fixed. There's debate about further revising it in a future release; but no consensus on if it needs to be faster or slower. People kept hard coding it as a constant so the legacy issues would make the tachyon situation look simple. More seriously: when the Universe was smaller and denser could the speed of light been higher, analogous to speed of sound in higher pressure and density materials?
- jfengel 5y agoDensity doesn't figure into it. It's about space itself, rather than the rate at which light travels. Light in a vacuum moves at that rate, which is a straightforward constant that figures into several other things. The space itself does change and you could try to redefine the formulas in terms of a changing speed of light, but it just makes it harder. The space metric fits very neatly into the Einstein field equations, and the expanding universe pops out of that directly. The acceleration doesn't, but it's a very simple tweak to make it do so. (Einstein had originally added that tweak to make the universe not expand, but then expansion was discovered.) If you change the speed of light you throw off chemistry, and all of the observations of distant galaxies show that chemistry still works. So a changing speed of light is unlikely.
- uh_uh 5y ago> The space metric fits very neatly into the Einstein field equations, and the expanding universe pops out of that directly. Is there a simple way to understand why? I don't have an understanding of the relevant math. It's a bit hard for me to imagine how we get from the axiom of "speed of light is constant in every reference frame" to an expanding universe. Unless there are other axioms used for this.
- adgjlsfhk1 5y agothe other axiom you need is that gravity and acceleration are the same. the speed of light being constant only gets you special relativity.
- sslayer 5y agoI've always maintained that we are slowly falling toward the center of a black hole that is larger than our current known universe. The rate of expansion is just the speed the universe is "falling, yet due to the absolutely fantastic size of the black hole it will take billions of years to collapse in on ourselves.
- DeRock 5y agoHere’s a website that explores that idea: http://www.flatuniversesociety.com/ http://www.flatuniversesociety.com/
- prox 5y agoI think a theory winning when it comes to “end of the universe - scary version” is what is known as vacuum decay : https://bigthink.com/hard-science/vacuum-decay-end-of-the-universe/ https://bigthink.com/hard-science/vacuum-decay-end-of-the-un...
- Zigurd 5y agoIs it not a bit odd to consider things that will happen long after the sun is a cinder "scary." There are enough genuinely scary things that could flash-sterilize the planet, or smash a big enough hole in it to end all complex life forms. Nearer-term scary things are likely to come from how poorly humans can adapt to long term life in space or on planets with different gravity. Time stretches beyond the ability of life to survive in both directions. Nobody will be around to be scared.
- prox 5y agoI agree my comment is way too antropomorphic centric. As you say, in terms of the timescales involved it might not be a time humans are around.
- thehappypm 5y agoAt the speed of light we’d all be gone. Even if the Mars colony was snuffed out first, we wouldn’t even know, since the information about the change wouldn’t be able to reach us before the decay did!
- cainxinth 5y agoDo you ever marvel at the fact that we have learned and continue to learn so much and yet still really understand basically nothing about why this universe exists, what its limits are, what’s driving its changes, and what its ultimate fate will be? We don’t know what we don’t know, and we’re trying to figure out how a black box works from inside an infinitesimally small corner of it. Frankly, I find it amazing we’ve worked as much as we have.
- beamatronic 5y agoWebb telescope will change everything, once again.
- tzfld 5y agoPeople tend to have unrealistic expectations from it lately.
- Aperocky 5y agoWhich is really nice, because nothing on Earth really matters when you consider the scale of the universe that we live in. Very blessed to be an observer though.
- wait_a_minute 5y agoIt is not the scale of the universe that would determine if Earth matters or not, but whether or not there is significance to the universe and to Earth. Significance conferred by observers or parties interested in these things. Example: $100 isn’t less or more just because of increasing or decreasing the physical footprint of the bill. We still confer a purchasing power of $100 to a $100 bill regardless of the bill’s physical dimensions. So the takeaway here is that it’s a non-sequitur to say that because of Earth’s small scale relative to the rest of space, nothing on Earth matters.
- Aperocky 5y agoYou're right, we still matter as people, but only for our own feelings and circumstances. It's humbling because it puts all that hubris away, which most people tend to have an excessive amount of - and begin to focus on living and achieving simple happiness instead of some illusion of grandeur.
- IsThisYou 5y agoAs far as I understand current physics, the solution seems simple: Just through some more "dark" matter in there, and the standard model is save again.
- known 5y agohttps://en.wikipedia.org/wiki/Timeline_of_the_formation_of_the_Universe https://en.wikipedia.org/wiki/Timeline_of_the_formation_of_t... looks strange and twisted turns
- MrYellowP 5y ago"Than it should be." Am I the only one who thinks that the wording roots in Hubris? And then, at the same time, I read "are flying apart" as if that's how it actually works. It doesn't. Wording it that way is misleading. I never read National Geographic, but I thought it's better than this.
- bumby 5y agoFrom the article: “faster than our best models of the cosmos predict it should.” It’s more an implied statement about the current models than the limits of human of human knowledge.
- marcyb5st 5y agoThe target audience of National Geographic are people with some science background but not researchers/experts. It a publication for the masses and so they have to tone down the technical lingo. For physics I read Nature, but for every other topic that might interest me but is above my knowledge level National Geographic works.
- MrYellowP 5y agoHonestly, I find that unacceptable. It's National Geographic. Could at least have some higher standards considering the above average audience. It's not technical lingo using the actually correct wording for the effects of the expanding universe. Galaxies do not fly apart, the space in between grows. The difference is significant, even though the observer wouldn't notice any. I know it seems like a non-issue, but in the end it's misleading all the people who would blindly believe NG to be accurate.
- aszantu 5y agoI thought that if more stuff collapses into singularity there might be something pushing outwards... Maybe like turning a balloon inside-out - which leads to the space-time expansion...
- Khaine 5y agoPBS Space Time has an excellent set of videos on this, including this one https://www.youtube.com/watch?v=72cM_E6bsOs https://www.youtube.com/watch?v=72cM_E6bsOs
- stagas 5y agoLike how accurate are these models? Could these be software or hardware errors? I mean, are these running on 1970 terminals in Fortran or is there real development going on? I imagine it's super hard to measure such tiny disrepancies in the cosmos when we are failing constantly in common modern software.
- ImprovedSilence 5y agoI mean, if it’s Fortran that’s been around since the 70s, it’s probably been around long enough that it is both better vetted for accuracy, and not burdened by “real development” affecting some static mathematical principals that the code is computing….
- stagas 5y agoValid argument, my main point though is how do we know whether these are not errors in the model generation and not in the universe acting in weird ways? It's not that you can make tests against the universe, you have to always rely on some algorithms giving you the results, which could be wrong and every institute could be using the same ones from the same vendor. Where are the data and what is the software is my worry.
- dqpb 5y agoOr rather, the models should be predicting faster expansion. I think it’s safe to say the Universe is expanding at exactly the rate it should be.