10 ms·
Fundamental physics sees worlds in grains of sand and infinities in hours
- sahil50 5y agoWhat if the cause of the cosmological redshift is continuous photon decay? Not galactic recession, but photon hubbling, or tired light? www.bigcircusmodel.org
- timmg 5y agoI'm not smart enough to know if that makes any sense at all. But it's a very intriguing idea. I'd never heard of it before.
- gnulinux 5y agoIf it were the case, photon decay would be measurable. https://physicsworld.com/a/what-is-the-lifetime-of-a-photon/ https://physicsworld.com/a/what-is-the-lifetime-of-a-photon/
- sahil50 5y agoE_measured / E_emitted = e^(-d / H'c) e is 2.718... d is distance of travel H' is 13.83 billion years, the continuous decay rate Rough calculations https://docs.google.com/spreadsheets/d/13aRdc1gZmsA3F-gKt5sKxPi3s9Pd4IHpgD5dlMao-cM/edit?usp=sharing https://docs.google.com/spreadsheets/d/13aRdc1gZmsA3F-gKt5sK... Data from https://ned.ipac.caltech.edu/Library/Distances/ https://ned.ipac.caltech.edu/Library/Distances/
- rootbear 5y agoThis idea has been around almost a hundred year. It is not supported by the evidence. https://en.wikipedia.org/wiki/Tired_light https://en.wikipedia.org/wiki/Tired_light
- sahil50 5y agoWhat if I could rebut all the rebuttals? - The analysis of supernovae light curves is calibrated in a way that presumes galactic recession. More detail here https://arxiv.org/abs/1711.11237 https://arxiv.org/abs/1711.11237. - The 2.7 K cosmic background radiation is consistent with non-expansionary, non-big-bang models. Cosmic temperature was predicted 50 years before Penzias and Wilson. https://en.wikipedia.org/wiki/Cosmic_microwave_background#Timeline_of_prediction,_discovery_and_interpretation https://en.wikipedia.org/wiki/Cosmic_microwave_background#Ti... - The mechanism for photon energy loss (can we call this "photon hubbling"?) is not scattering by free electrons. I speculate it is the cost of traveling, of a photon forging its way through spacetime. E_t / E_0 = e^(-Ht). In the act of moving, the photon is warping spacetime. It doesn't travel for free.
- Filligree 5y agoIt’s intuitively a reach, because photons don’t move. From a four dimensional perspective—which is the correct one, let’s not forget—the distance between a photon’s emission and absorption event is always zero. “Tired light” would require the photon to spontaneously lose energy based on the Manhattan distance of the path it takes. That distance can be arbitrarily large, sure—a photon can cover the entire universe before absorption—but it isn’t the path the photon actually takes, so it’s difficult to imagine why it would matter.
- hvidgaard 5y ago> From a four dimensional perspective—which is the correct one, let’s not forget—the distance between a photon’s emission and absorption event is always zero. That would require the emission and absorption events location in the space to be the same would it not? Or do you mean that a photon does not experience time, so relative to the photon it simply travel instantaneously from emitting coordinate to absorption coordinate?
- gizmo686 5y agoThe distance metric for flat spacetime is given by: ds^2 = dx^2 + dy^s + dz^2 - cdt^2 For a particle traveling at the speed of light, this gives ds=0.
- creata 5y ago> That would require the emission and absorption events location in the space to be the same would it not? I think they're referring to the distance in Minkowski space,[0] where the time component and space component cancel out for light. [0]: https://en.m.wikipedia.org/wiki/Spacetime#Spacetime_interval https://en.m.wikipedia.org/wiki/Spacetime#Spacetime_interval
- sahil50 5y agoWhere does your claim that photons don't move come from? Very simply, the Sun is 8 minutes from the Earth. The photon is most definitely moving from the Sun to the Earth.
- mojuba 5y agoSorry for meta, but to downvoters: please don't downvote a what-if question that - well, questions an established theory in a casual conversation. A lot of interesting, disruptive things in science start with a question!
- czzr 5y agoWithout taking a position on downvoting - this is true for new interesting questions, at some point you have to move past ones already eliminated as reasonable possibilities.
- smrk007 5y agoOTOH, I think this position is relevant only from the perspective of new scientific inquiry — it’s worth asking questions that have already be asked when learning / acquiring knowledge! Sure, someone could find this information on Google, but misinformation too, so I think it’s worth asking in this sort of environment so we can all more deeply understand existing theory, etc.
- deleted 5y ago[deleted]
- SketchySeaBeast 5y agoThis seems very much like a disingenuous what-if - not a desire to actually seek an answer, but an attempt to convince people into believing what they do by posting a link to a very biased site.
- gliptic 5y agoWhile the comment says "What if", the site linked is more "All physics is wrong, this is how it is" and presents some model that has been disproven by evidence over and over. I think crank physics isn't worth discussing when presented in that fashion.
- sahil50 5y agoThank you
- sandgiant 5y agoNot supported by data. There is plenty observational evidence that the redshift is due to cosmic expansion, e.g. galaxy surface brightness evolution, CMB, time dilation, the list goes on. The website you link poses a number of unsubstantiated claims without any answer to the numerous problems it raises. Then he links to this hilarious notebook; https://colab.research.google.com/drive/1K1qoUFvqZp1fWbpcKJWq63nflgwS0ZHh?usp=sharing https://colab.research.google.com/drive/1K1qoUFvqZp1fWbpcKJW... I don't mean to sound rude but this doesn't look like the work of someone who has spend any considerable amount of time actually studying the Universe.
- sahil50 5y agoWhat if I could rebut all the rebuttals? - The analysis of supernovae light curves is calibrated in a way that presumes galactic recession. More detail here https://arxiv.org/abs/1711.11237 https://arxiv.org/abs/1711.11237. - The 2.7 K cosmic background radiation is consistent with non-expansionary, non-big-bang models. Cosmic temperature was predicted 50 years before Penzias and Wilson. https://en.wikipedia.org/wiki/Cosmic_microwave_background#Ti https://en.wikipedia.org/wiki/Cosmic_microwave_background#Ti... - The mechanism for photon energy loss (can we call this "photon hubbling"?) is not scattering by free electrons. I speculate it is the cost of traveling, of a photon forging its way through spacetime. E_t / E_0 = e^(-Ht). In the act of moving, the photon is warping spacetime. It doesn't travel for free. And, what's your view on Dirac's large numbers hypothesis?
- pfdietz 5y agoThis would not give blackbody radiation, and is ruled out by observation. http://www.astro.ucla.edu/~wright/tiredlit.htm http://www.astro.ucla.edu/~wright/tiredlit.htm
- sahil50 5y agoWhat if I could rebut all the rebuttals? - The analysis of supernovae light curves is calibrated in a way that presumes galactic recession. More detail here https://arxiv.org/abs/1711.11237 https://arxiv.org/abs/1711.11237. - The 2.7 K cosmic background radiation is consistent with non-expansionary, non-big-bang models. Cosmic temperature was predicted 50 years before Penzias and Wilson. https://en.wikipedia.org/wiki/Cosmic_microwave_background#Ti https://en.wikipedia.org/wiki/Cosmic_microwave_background#Ti... - The mechanism for photon energy loss (can we call this "photon hubbling"?) is not scattering by free electrons. I speculate it is the cost of traveling, of a photon forging its way through spacetime. E_t / E_0 = e^(-Ht). In the act of moving, the photon is warping spacetime. It doesn't travel for free.
- jakear 5y agoPlease don’t repeat the same comment over and over, it comes off as spam even though that’s not what you intended. This doesn’t even address this particular parent’s question. Better would be to make the comment once, where it is most appropriate, then give specific responses to other threads, perhaps linking to the one comment if it’s relevant.
- pfdietz 5y agoThe supernova light curve data is red shift vs. timescale of the light curve. This doesn't make any assumption about galactic recession. And it's incompatible with tired light models. No, the CMBR is not consistent with non-expansionary models. Tired light may get the shape of the CMBR spectrum right, but it fails to get the intensity right unless there's an extreme coincidence that we just happen to be living at exactly the right moment. This was all explained in the page you think you were rebutting, so please go re-read it, this time for comprehension.
- bsedlm 5y agoReminds me of Cyclic Conformal Cosmology theory (backed by Roger Penrose). As far as I can tell, the CCC theory says that the big bang did happen but that the universe is cyclical. i.e. once the universe reaches 'heat death' another big bang happens.
- sahil50 5y agoPenrose's observations of evaporated black holes in the cosmic background radiation map are really interesting. This is a big reason to think there are structures older than 13.8 billion years.
- jermaustin1 5y agoI'm not smart enough to understand most of cosmology or astrophysics, but the way that site is presented makes me feel that it is quackery. The fact that there are only a handful of sentences makes me feel it is trying to appeal to people with low science literacy. I'm not trying to discount it, but that home page with 12 photos of various galaxies, and then 4 blurbs of text, then a full screen YouTube video just feels "unscientific".
- manojlds 5y agoI find this a bit funny as we just can't know what we don't know.
- adrianN 5y agoBut we have pretty tight bounds on how much the things we don't know can influence the things we do know, because we have tons of observations. We are for example quite sure that there is nothing on Earth that makes apples fall upwards and we can be reasonably certain that this is also true on other planets.
- andi999 5y agoIn our planetary system, yes. Outside evidence gets worse.
- menzoic 5y agoI don't think the bounds are tight or it can ever be. If you don't know something, you just don't know. We don't know much about negative mass or if gravitons exist yet, two things which could make apples fall upward. There's nothing that allows us to say with absolute certainty that it isn't possible, especially on planets billions of light years away that we have no visibility into at all.
- mjburgess 5y agoWe can't assign 0 probability to any position on the grounds of "humility", but "negative mass" assuming our best theories are true is probability-0. The relevant probabilities when making predictions are under the best theoretical assumptions we can make; which includes that the universe follows the same laws of physics everywhere. It isn't very interesting to observe that, absent these, no proposition has a zero probability. Eg., you dont get to claim that given the laws of physics it is possible to have a negative mass, because given no laws of physics, it is possible. When you arent given any information at all, all propositions are equally likely. Propositions like, "the universe has a maximum speed" aren't merely observational. They follow with probability-1 from fundamental universal laws of physics. If this is false, all of physics is false.
- leephillips 5y ago“Fundamental” physics is just the physics of what we happen to be able to observe with the technology available to us at the moment. Newton was creating the fundamental physics of his time. And a century from now, even if in our generation we succeed in erecting a complete theory that explains everything we have ever seen, physicists will be working on “fundamental physics”. And we still won’t have a good enough handle on turbulence.
- amelius 5y agoIsn't turbulence more a mathematical problem than a physical one?
- ISL 5y agoExperiment is still the arbiter of truth; it enables us to discern which math correctly describes nature.
- potatoman22 5y agoWhat's the distinction?
- leephillips 5y agoI don’t think it’s considered an interesting mathematical problem, although it is related to some interesting theorems about singularities in the fluid equations. It’s of interest to applied mathematicians, engineers, and, perennially, to physicists and artists. For example, Leonardo, who was all of these things.
- dasudasu 5y agoSolving turbulence is quite literally a millenium prize problem with a 1 million USD price tag to it. Solving it would make you famous and almost certainly give you a Fields medal as well. It’s just a particularly difficult problem.
- leephillips 5y ago
- morpheos137 5y agoI think language and especially writing are more extrordinary achievements. Physics is useful for engineering purposes in a civilization. Civilization would not exist without language.
- FinanceAnon 5y agoI think ability to walk upright is a bigger achievement
- nightcracker 5y agoWe could build modern society strictly crawling, without language we would still be hunter gatherers in small packs.
- leephillips 5y agoI’m more impressed by the ability to metabolize oxygen. Nobody will ever beat that.
- binarymax 5y agoOr opposable thumbs!
- morpheos137 5y agowell creatures that can't walk upright are not human so bipedalism can not be counted as a human achievement. Anyway maybe you are right in a broad sense. My point was that extolling physics above all other human achievements seems lopsided to me. Physics is useful for engineering purposes. It is not some all encompassing philosophy or technology that covers all aspects of human interaction with the universe. writing is certainly used far more broadly than the schrodinger equation.
- forinti 5y agoUnfortunately it comes at a high price. Who doesn't have backache?
- throwawaycities 5y ago
- yamrzou 5y agohttps://archive.is/t2P97 https://archive.is/t2P97
- gexaha 5y agoHumanity’s most extraordinary achievement is that we are still alive, despite having 8 or 9 countries with nuclear weapons
- lapetitejort 5y agoFundamental physics helped with this accomplishment!
- amelius 5y agoDepends on how you read it.
- revscat 5y agoFor now. Going to be much more difficult for this to continue when the average temperatures are 10° higher. And I can very well see a situation arise where nuclear weapons are used because of pressures from climate change, say between India and Pakistan. I think we were able to survive the Cold War because the threat was literally explosive: highly visible and quickly understandable. For longer term, quieter threats like climate change humanity does not appear to have the capability to avoid its destruction, or even the will to do so.
- lordnacho 5y agoI mean it's an achievement, for sure. Understanding what the universe is made of is pretty massive. But is it the most extraordinary one? I think more towards how we have escaped our constraints as animals: - It's a problem to eat too much now, contrary to the experience of all creatures other than modern people. - We no longer live in one environment. In fact we create our own, in many places. - We don't mind if the sun goes down, we can replace it, temporarily. - We can use energy that was captured a long long time ago. - We don't even need to reproduce all that much to survive. It's pretty much an expectation that we'll live past childhood, it's considered a massively unfortunate tragedy if your kid dies these days. - We can interact with people who are far away, as if they are right in front of us.
- amelius 5y agoBut don't many of these things depend on fundamental physics in some way?
- 0-_-0 5y agoOnly the last one
- ilikeatari 5y agoInterestingly enough most of these are also possible because of advancements in physics.
- lordnacho 5y agoBut our advancements in physics are also only possible because of these things.
- javajosh 5y agoThis is the classier form of the "who would win in a fight between Thanos and Darkseid" internet discussions. But yes, physics is amazing, but it doesn't exist alone. Math is particularly important, but also chemistry and engineering all co-exist in a positive feedback loop. (If I had to isolate the single greatest insight in the modern world, it would be Descartes introducing the notion of number as different than "the length of a line segment". This change in perspective made possible all the math and physics that came after. This perspective is now so common as to be invisible, so for someone to see something so foundational, but so unknown, it is really remarkable.)
- civilized 5y agoCould you elaborate on what Descartes did? He's known as the inventor of coordinate geometry, which seems to rely on the notion of number as the length of a line segment (two number lines placed perpendicular to one another uniquely identify any point on the plane). Are you talking about his work on algebra or other things?
- javajosh 5y agohttps://en.wikipedia.org/wiki/Ren%C3%A9_Descartes#Mathematical_legacy https://en.wikipedia.org/wiki/Ren%C3%A9_Descartes#Mathematic... I will look up the specific paper where he proposed that a squared number need not represent only an area, for example.
- civilized 5y agoAh, I get it now. Descartes suggested that the representation of numbers need not be dictated by the geometric interpretation of how they were calculated. For example, a^2 doesn't have to be represented as an area, even though geometrically it would be the area of a square.
- javajosh 5y agoThe "paper" was La Géométrie[1], originally published as an appendix(!) to another work, Discourses on the Method [2]. Not sure why all the downvotes. Oh well. 1 - https://en.wikipedia.org/wiki/La_G%C3%A9om%C3%A9trie https://en.wikipedia.org/wiki/La_G%C3%A9om%C3%A9trie 2 - https://en.wikipedia.org/wiki/Discourse_on_the_Method https://en.wikipedia.org/wiki/Discourse_on_the_Method
- Invictus0 5y agoI'm truly humbled to be alive at a time when so many of the biggest questions that frustrated our ancestors have more or less accurate answers. We know about the big bang, the atom, black holes, the speed and nature of light--how majestic and beautiful it all is. Thank you to all the physicists that got us here, and godspeed to the physicists of the future!
- paganel 5y agoThat's a very euro-centric view to sat that "humanity’s most extraordinary achievement" is something that has been developed/found out/whatever you want to call it mostly in the parts of the world inhabited by white men. Like someone else mentions in this thread, probably "humanity’s most extraordinary achievement" was standing upright in the Ethiopian plains, or language or even writing (which showed up in several parts of the world) but, again, to label a thing invented by white men (paid to develop deadly weapons, among other bad things) as the "humanity's greatest thing ever" should not be ok.
- atdrummond 5y agoAs a mixed man (half North African, half Western European) this comes across as needlessly antagonistic. There’s nothing in the article to indicate that this was picked due to the race of these inventors nor is there any immediately clear indication of unconscious racism. I know I’m probably biting at obvious flame bait here but this comment doesn’t really seem to be in the spirit of this site’s goals for quality discourse.
- paganel 5y ago> There’s nothing in the article to indicate that this was picked due to the race That's the worst type of racism, the one so well internalised that you don't realise is there, that's what makes it more dangerous compared to the "redneck"-out-in-your-face variety. I'm pretty sure that the author of article wasn't aware of his/her implicit euro-centric bias, he/she comes from a culture where things like "fundamental physics" are seen as representative of the group's intellectual nous (where the "group" ~= people raised up/educated in an euro-centric culture with euro-centric values), and hence as representative of the world/humanity as a whole. I take issue with this "the bestest thing made by white men" -> "the bestest thing made by humanity" transition.
- jakear 5y agoWhite men are not the only folks involved in researching fundamental physics and you know it. You comment devalues their work more than anything on this page. Your account is old enough I’d expect you to know what dang’s about to say already, the whole “we’re steering a ship and don’t want to get sucked into dialectic black holes” thing.
- talkingtab 5y agoA view of the universe from Flatland.
- 0-_-0 5y agoI don't think any of the physics we know is truly fundamental.
- taliesinb 5y agoWhy do you think that? (I happen to agree)
- 0-_-0 5y agoWell, unless the most fundamental laws of physics were intelligently designed (which I doubt and which would lead to a recursive argument anyway) they must be the simplest that can lead to intelligent creatures arising. Current physical laws are too complex to be the simplest possible such laws.
- Koshkin 5y ago"Fundamental" is a direction of research in physics.
- cbm-vic-20 5y ago"If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generation of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis that all things are made of atoms — little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied." --Richard Feynman
- Koshkin 5y agoWhat's interesting is that the Ancient Greeks "knew" this but it took two thousand years to actually prove it. Now the question is: how long can it take to confirm one of the quantum gravity theories? (Quantum gravity remains the biggest unsolved problem in fundamental physics today.)
- mannykannot 5y agoYou are right to put "knew" in quotes, as Democritus' speculation had no more support than Thales' "all is water", the four elements, the bodily humors or the celestial spheres. Knowledge lies at least as much in the justification of a fact as it does in the proposition itself.
- ithinkso 5y agoThis is survivorship bias. They 'knew' it only retrospectively, they also 'knew' a lot of different incorrect theories. In some sense one could argue that Aristotle halted the progress of physics for about a thousand years (not related to atoms, but a general comment of what the Ancient Greek 'knew')
- mannykannot 5y agoIf the progress in physics really was halted for a millennium (actual physics was not moving that fast beforehand), any blame must rest with the intellectuals of that time.
- state_less 5y agoI sometimes think about how startling it must have been for our species to realize we orbit the sun, the earth is round, then to find that we live in a galaxy, one amongst so many it boggles the mind to imagine. Given all these revelations, when I think about what may still be revealed, it’s enough for me fall to my knees and cry about what a fool I almost surely am. I dust myself off and carry on as best I can, hoping to learn a little more than I did the day before, knowing there are good folks by my side to share the path we’re on.
- morpheos137 5y agowhat does it really mean to "orbit the sun?" We follow an elliptical path around the sun from the perspective of the reference frame of the sun. From the perspective of the reference frame of the earth the sun and planets move around us in complicated epicycles. From the perspective of an external reference frame, outside the solar system, the earth moves in a sinusoidal manner as the sun orbits the galaxy. At the largest scale space is expanding and no orbits are cyclical. We never return to the same space twice. Rotation is said to be absolute while linear motion is relative but since space is expanding at the largest space and time scales are not orbits illusory? Due to gravity objects follow curved paths through space and time as the fabric of the Universe expands but if you think about it you never really return to the same place twice so might also at large scales apparent angular motion also be relative or convergent on linear motion, e.g. through fourier decomposition?
- karmakaze 5y agoI don't think there should have been a reason for any of these discoveries to be mind-boggling. It's the premise that we knew anything before we knew, e.g. religious indoctrination that made it so. Would the confirmation of aliens be mind-boggling today? For some yes, why? But on the sheer vastness of what we didn't know, it seems like that's shrinking in relevance. There are of course dark areas, black holes, quantum gravity, and so on, but they are farther and farther at the edges of scale. Not as world-changing as discovering the second island after your own, or a continent, planet, or solar system. Each one has less practical impact.
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- Koshkin 5y agoAn impressive achievement it is. But a general sentiment today seems to be that the process somehow has stalled or perhaps has slowed down dramatically - despite the fact that there are more scientists involved than ever before. Does this mean that we are at, or close to, the limit of what we can possibly know? Or even "guess," like in the case of M-theory (or other quantum gravity endeavors)? Some say that fundamental physics is essentially done, and the future progress lies with biology (which, one hopes, will lead to further advances in medicine, in particular).
- ssaddi 5y agoPhysics allows practical applications of mathematics, whether using sine/cosine to explain wave motion or complex calculation of celestial objects, like planetary orbits. Yet it still cannot explain quantum mechanics, i.e. interactions of subatomic particles because there the general laws of physics do not work. So basically it just comes down to how much of physics knowledge that humanity has obtained up to now really explains the universe - and it seems there are still vasts gaps in science that still needs to be filled.
- Koshkin 5y agoFYI quantum (field) theory is the best and the most accurate physical theory in existence today.
- echopurity 5y agoFWIW supersymmetry and string theory were never convincing to people who value science, empiricism, epistemology, etc. This sort of pseudo-scientific hype is necessary to keep the money flowing under capitalism. See also "artificial intelligence", etc. https://arxiv.org/abs/0905.2658 https://arxiv.org/abs/0905.2658