7 ms·
The closer we look at time, the stranger it gets
- huflungdung 9mo ago[dead]
- mock-possum 9mo ago[dead]
- andreashaerter 9mo ago[dead]
- dotancohen 9mo ago> Combining quantum mechanics and General Relativity is all well and good, but there‘s one key mystery it doesn’t address: why does time only seem to flow in one direction? Could the problem just be with us? When time flows backwards, we lose the ability to perceive the events that came after the "current" event. As it flows forward again, we have more time in our context window. We are able to perceive only those events that have occurred before the current event. Time still flows and ebbs, we just lack the ability to sense it just like a cork in a river doesn't feel the water flowing past.
- hnfong 9mo agothere is no flow per se, as it’s a subjective experience. it’s just that our current environment (specifically human environment) is predominantly structured in a way that the past makes an imprint on the present (in terms of biological memory, historical records, etc) and the future generally being unpredictable because we kinda don’t want it to be too predictable (eg you don’t want to be too predictable when a tiger is chasing you for example) but in other environments (talking about same universe here!) the future is more predictable than here on earth, for example motions of planetary bodies can be predicted way in advance within error bars as in the past, and when you have that kind of relatively symmetrical system, any subjective experiences within those systems would be much less inclined to feel that time flows on way or the other. (of course, the only kind of subjective experiencers we know are made of biological stuff which structurally remembers the past and leaves the future open as form of evolved ability, so this timelessness experience may be harder to imagine for us)
- klipt 9mo ago"Time is an illusion, lunchtime doubly so"
- charlieflowers 9mo ago"Ohh, time flows _that_ way for you."
- alex77456 9mo agoIf you consider a person, their brain in particular, flowing backwards in time, the brain becomes a prediction tool. Events-memories (neural connections) appear out of nowhere (from the state of being 'forgotten' in the forward time flow) then completely disappear when the corresponding event happens, annihilating its 'predicting' memory.
- hnfong 9mo agoThe brain does want to predict (in fact I think that's what it's suppose to do), the problem is that the Earth is rather chaotic and unpredictable. If you subject a brain-like neural network to watch planets and stars orbiting around each other and rewarding it for getting things right, it will likely do quite well.
- alex77456 9mo agoNot that kind of predict. And this reverse-time brain instantly forgets things it saw for the last time. Consider a black box. A person opens it, sees a dice with a number, closes it. In our version of the time flow, the person finds out there's a dice and remembers it. In the 'reverse time' persons brain, they would know they would open the black box and know which number they will see. Then they will close it and completely forget what was inside forever.
- nwatson 9mo agoThe past that we have yet to subject to our subjection also is effectively future. Supplication for unknown outcomes surely already determined in the objective past wrt the present time still makes sense. The Divine Successive Relaxation with physical laws as the substrate, and the choices of human free will, human petition and desire, and Divine Will And Intention as boundary conditions, will solidify objective reality into a coherent whole in Open Theism.
- russdill 9mo agoFor the "canonical" physics explanation, see: https://en.wikipedia.org/wiki/Past_hypothesis https://en.wikipedia.org/wiki/Past_hypothesis You can happily run physics backwards and forwards, and there's no difference. But assuming that entropy was very low in the distant past is very useful and lets us talk about fascinating things, like what happened last tuesday (or 12 billion years ago) If you just know the current state of the a system, there isn't really any difference between running time backwards and forwards. Of course, if you know exactly the state of every particle, field, etc, and the past hypothesis is true, running time one way will lead to lowering entropy, and the other way will lead to raising entropy. But if you're a mere mortal and just know the macrostate, either way you run time, the entropy of the system will increase.
- deleted 9mo ago[deleted]
- slyfox125 9mo agoWe understand "time" in the context that we must: to subsist in order to procreate. The extent it exists outside of our own perception as we imagine it does, is debatable. Ultimately, time is our sensory interpretation of the world around us to facilitate our survival and thus, we may never make sense of it outside the constraints it exists within.
- ricardobeat 9mo agoWe know empirically that time only flows in one direction, it can’t be described as just a perception. You’d have had at least the tiniest of evidence that time sometimes flows backwards.
- slyfox125 9mo agoHow do you know anything outside of your perception is true? All things boil down to a philosophical argument. The simplest answer is that "time" as we imagine it is a product of our interpretation and the true nature of "it" is hidden from us.
- ricardobeat 9mo agoThis is about time as it relates to our understanding of the physical world through science. You might as well say matter is an illusion, nether is relevant to this discussion.
- slyfox125 9mo agoYou believe it is irrelevant - I believe it is relevant. I argue matter itself has more basis in reality in that it cannot be as easily explained away as time. In the context you're speaking in, there is much more evidence and logic to support the existence of matter. My point is that time as we believe it exists, is a construct that has meaning to us because of its benefit to our survival, rather than it being an objective reality.
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- ChuckMcM 9mo agoThis was perhaps my favorite part of Physics 390 ("modern physics") which was about quantum dynamics and relativity. The speed of light is defined in terms of a velocity (~300,000,000 m/s) but if you were traveling at the speed of light time stops (which keeps the rule that its constant in all frames of reference). That and time passes more quickly at higher altitudes and these days we can actually measure that. Wild stuff.
- tacker2000 9mo agoAlso see the twin paradox, which is related to this and equally fascinating. If one twin stays on earth and the other makes an intergalactic trip (with the speed of light), upon return, the one on earth will have aged much more than the one on the trip.
- Tor3 9mo agoThe paradox isn't actually when the twin is returning, the paradox is seen during the trip away from earth. Both are observing each other through telescopes, and both can see the clock on the wall in each other's home (a house, or for the twin, his space ship. Which has got a big window). And both can observe that the other twin's clock is moving at a slower pace than their own clock. And that's the paradox. (p.s. the spacefaring twin doesn't have to move at the speed of light, and indeed cannot, it's enough to move at a "relativistic" speed, i.e. fast enough that this is actually measurable. With today's clock that doesn't have to be very fast actually)
- MaxikCZ 9mo agoThe fact that at speed of light time stops is just so bonkers to me. A photon is, from its point of reference, at the point of creation and at the point of destination at the same "time". Its literally seeing both parts of the universe at the same time, and since its traveled some distance over that time it cannot perceive, its essentially connecting 2 points in spacetime. If I understand it correctly, every photon exists, from its point of view, for only infinitely small amount of time (similar to how virtual particles do exist from our point of reference), but for us its so easy to "play" with the photon along its path, giving us plenty of time to even decide what we want to do with it after it has already been created. Its just so bonkers that time can be perceived such differently depending on frame of reference.
- robot-wrangler 9mo agoIANACosmologist, but in for a penny, in for a pound. If one accepts weirdness along the lines of extra spatial dimensions and mathematical singularities made physical, why not throw in a few extra dimensions for time or why not have imaginary time (in Hawking's sense)? > One might think this means that imaginary numbers are just a mathematical game having nothing to do with the real world. From the viewpoint of positivist philosophy, however, one cannot determine what is real. All one can do is find which mathematical models describe the universe we live in. [1] [1] https://en.wikipedia.org/wiki/Imaginary_time https://en.wikipedia.org/wiki/Imaginary_time
- actionfromafar 9mo ago"describe our observations of the universe"
- deleted 9mo ago[deleted]
- juleiie 9mo agoCan anyone actually understand this at this point? I will reread it like three times maybe the third time is the charm
- msuniverse2026 9mo agoIn Anthroposophy or Western occult science time runs in reverse in something we call the etheric body. The physical body on the other hand is something that experiences the world through organs that register only the present moment. It can't perceive what no longer physically exists or what has not yet manifested physically. The etheric is a time-body, containing the complete formative record of one's biography and is the source of memory, the brain is sort of a receiving organ for it, though the whole body utilises it. Upon death the etheric body opens up and turns itself inside out and as you identify less with your physical body and more with your etheric body your perception of time is now in reverse. Your entire life tableau is opened in front of you, and as your spiritual organs of perception once "facing inwards" to your interior are now "outward-facing" and working backwards you start to see the effects of all your choices and actions from the perspective of its consequences. This is the source of those "life flashes before your eyes" moments people with near death experiences go through. Only for very unconscious people is it a hell-like experience. Even if you lived a rather thoughtless and abusive life it is said that it can still be a time of reflection and learning. Eventually after viewing your entire life "inside out" your perception opens up to your pre-birth condition, the etheric body sloughs off (being made of elemental beings itself) and is picked up and put together with all the karma of your previous lives for your next go-around on Earth. You liberate the elementals in your etheric body (which are just below humans in the spiritual hierarchy) by growing spiritually either during life or in the etheric condition and eventually, hopefully, move up the spiritual hierarchy to a being that liberates humans, an Angel. Thought maybe HN might be interested in some other conceptions of time. :^)
- juleiie 9mo agoInteresting that this comment appeared precisely when I needed and wanted to see it on the most unlikely of websites. Thanks for your insights
- hikingsimulator 9mo agoGiven how "western occult science" is just magical thinking and pseudo babble, it hardly fits on HN. Additionally, "western occult science" typically glosses over its 1920-1940s roots and branches. Wondering why...
- tornikeo 9mo agoNot related to this article, but this post seems to attract so many cranks. Just look at other comments. The amount of weird (out-of-touch) comments on this post is fascinating.
- deleted 9mo ago[deleted]
- f3b5 9mo agoSome of those might be AI accounts that found an ambiguous topic for upvote farming.
- oersted 9mo agoWhat might be the motivation for upvote farming on HN? There is the personal satisfaction of a carefully written comment being acknowledged and validated, but otherwise? You do get some minimal upgrades with enough karma, like the ability to downvote. But it's not like you get any priority or special treatment, and the numbers are not exposed unless you open individual profiles. I suppose it could be useful to give legitimacy to bot accounts to be able to inflate upvotes of some posts, but from what I've seen vote-ring detection is really good on HN.
- thom 9mo agoAll of this should be familiar to the average programmer. The Creator (I call him Colin), rushed for time and bereft of more elegant ideas, has widely deployed lazy loading as a solution to the finite processing power of the universe. Almost all of physics (the speed of light, the expansion of space, quantum entanglement) is an answer to the question of how the universe (and indeed Colin himself) can avoid doing too much work.
- ndsipa_pomu 9mo agoI bet Colin gets annoyed every time we point a telescope at far away objects as he has to rush around behind the scenes and paint in all the details.
- smokel 9mo agoWait until you hear how he performs garbage collection.
- ndsipa_pomu 9mo agoDoes it involve sweeping stuff under black holes?
- discomrobertul8 9mo agoNoah's Automatic Reference Counter
- actionfromafar 9mo agoArena allocators?
- jesuslop 9mo agohe sends the electron both slits so is also doing some complex-numbers montecarloing. Since he has infinite ram he can sum every-single-path.
- finghin 9mo agoSEP is always an interesting companion to these articles about physical fundamentals. [0] [0] https://plato.stanford.edu/entries/time/ https://plato.stanford.edu/entries/time/
- rausr 9mo agoI'm only slightly disappointed that this is not the "Someone Else's Problem" version of SEP.
- nrhrjrjrjtntbt 9mo agoBad for the BBC brand to have this site licensed which is riddled with ads. Turning off JS does the trick though.
- ndsipa_pomu 9mo agoOne problem that I have with trying to understand "time" is that we can't measure how quickly it "flows" or at least how quickly we travel through it.
- ben_w 9mo ago> we can't measure how quickly it "flows" or at least how quickly we travel through it. I don't understand this, because it seems like "with a clock" is too obvious an answer, so surely you can't have meant what it sounds like it meant?
- card_zero 9mo agoIf we say that seconds "pass", at what rate do they pass? Could they pass at some rate other than one second per second? That would entail outer seconds (second seconds, if you like). Which also have their own rate at which they pass, so now we need a third-level "flow of time", and so on. So to say seconds "pass" is describing something else. They aren't moving.
- raldi 9mo agoYou’ve never listened to a podcast at a rate of 1.5 seconds per second?
- oersted 9mo agoI feel like you are overthinking it a bit, entangled in semantics. You can take any process that has a fixed frequency (like a clock), and measure the change in frequency in different situations, from the same point of reference. Moving that device at different speeds or into different places in a gravitational field. This is why satellite clocks move at a different rate than those on Earth. Practically speaking, that's really what we care about when we talk about the speed of time. If some process takes a certain amount of time to complete, sending it to space and back, without changing anything else about it, might make it complete earlier from our point of reference. It is actually about seconds per second, and there is an inner and an outer second as you say. There’s nothing wrong with that, because it is always a relative difference between two frames of reference. There are the seconds for our point of view, and there are the seconds for the device we are sending to space and back. I think you are struggling to understand how to measure the absolute speed of time, but there’s no such thing, it’s always a comparison, it is relative.
- zkmon 9mo agoWhat's new here? I spent a few minutes reading it end to end, and it sounds like slop without new info.
- grishka 9mo agoThere's another inscrutable mystery in physics, the nature of consciousness. Time might as well be an artifact of that. I'm surprised this article doesn't mention this possibility. Here's an interesting lecture about it: https://www.youtube.com/watch?v=YusrOYGAhqM https://www.youtube.com/watch?v=YusrOYGAhqM
- drcongo 9mo agoI got downvoted on here not so long ago for mentioning time as an emergent property of quantum consciousness so maybe it's controversial.
- grishka 9mo agoI was downvoted for saying that our cosmological model might be wrong because "dark matter" sounds like a crutch. Now JWST has collected enough evidence that it might, in fact, be wrong.
- IAmBroom 9mo agoDark matter absolutely is a crutch. It's "dark" in the sense that the (fabled) Dark Ages were dark. They didn't have more cloud cover then. And dark matter is 'dark' as in 'inobservable, except by gravitational attraction'. So we admit it might not even be "matter" by any definition we have; it's just what we're calling this invisible, untouchable, silent elephant in the room. That is very heavy. And might not be an elephant. Honestly, "invisible matter" might have been a better term, but that too would have been misinterpreted.
- grebc 9mo agoHonestly, just saying the maths doesn’t always work is much more approachable than dark/invisible matter.
- IAmBroom 9mo agoThe first problem with the nature of consciousness is describing what you mean by it. Try, and I guarantee you that someone will find a sponge, Apple product, or bathroom slipper that meets that definition. Electro-magnetic radiation, on the other hands, is highly describable in precise, testable, repeatable terms. When you can state Maxwell's Laws of Consciousness, we'll talk. And rename them "Grishka's".
- FIGYJ 9mo ago[dead]
- user3939382 9mo agoI have a solution that addresses this. Will publish soon, it’s a slow process.
- Antibabelic 9mo agoWould you like to share any details?
- user3939382 9mo agoI would love to. Unfortunately when you’re talking about physics the community doesn’t welcome casual conversations, that’s been my experience. If you start with anything less than a formal proof all the hackstchuallys come out. So I will start with the proof, soon. Working with some academics on peer review now.
- IAmBroom 9mo agoOoh, do the unified-field thing next!
- user3939382 9mo agoYou are everything that’s wrong with STEM. Sarcastic and angry with 0 contribution.
- My_Name 9mo agoThey nearly have it in the article but don't take the next step, which is to realise that time is gravity. We are falling towards the future at the speed of causality. You can slow your experience of that by travelling really fast, or by being near something with a large gravity. Quantum particles can simply ignore gravity and time while we are forced to feel their effects due to our size, like a mote of dust can ignore gravity, but a brick can't.
- throwaway77385 9mo agoA mote of dust doesn't ignore gravity in a vacuum ;)
- IAmBroom 9mo agoEven a photon can't manage that trick.
- sigmoid10 9mo agoWell, almost. Because these usual descriptions you give here are approximations. Yes, to the first order, gravity is expressed as the effect on time in general relativity. So you could describe how planets move simply by calculating how they move differently through time. But in the full picture, the way you move through space or near strong gravitational fields also influences your experience of space itself. So the ultimate realization is that gravity is space and time. Or spacetime. Basically exactly what the article says when it references general relativity. And it holds as well for quantum particles. They experience spacetime just as well as we do. The ultimate question is, does spacetime itself also come quantized when you look close enough? This is the true head banging one that noone knows.
- euroderf 9mo ago> The ultimate question is, does spacetime itself also come quantized when you look close enough? Isn't there some sort of "quantum foam" ? So it's going to be difficult to define a metric ?
- deleted 9mo ago[deleted]
- anal_reactor 9mo agoThe ads on this website are atrocious.
- amanaplanacanal 9mo agoI recommend an ad blocker. I didn't see any ads.
- anal_reactor 9mo agoThe Japanese use this one simple trick to reduce sleep apnea - it's...
- netfortius 9mo agoI strongly recommend reading Carlo Rovelli, starting with "The Order of Time"
- euroderf 9mo agoI've read that cats can remember the future. Let's see someone fit _that_ into their theories.
- IAmBroom 9mo agoYes, the internet is full of BS. Good for you for reading!
- sbuttgereit 9mo agoI think I like Tim Maudlin's approach to the question. Time isn't all that mysterious: it's simply fundamental meaning it cannot be explained has being the sum of some things more fundamental. The argument is that's where the difficulty lies for many is they want to express time as though it's a composite, and it just isn't. So the best you can do is explain time by referencing those other aspects of existence which incorporate time. Here's a much longer take from Tim Maudlin, "Tim Maudlin: A Masterclass on the Philosophy of Time" (https://youtu.be/3riyyEmWwoY?si=9aI-bETWcNpdjMW9 https://youtu.be/3riyyEmWwoY?si=9aI-bETWcNpdjMW9), Tim Maudlin is Professor of Philosophy at NYU and Founder and Director of the John Bell Institute for the Foundations of Physics. The podcast is Robinson Erhardt's.
- grebc 9mo agoI like Tim, his arguments come across as an honest attempt to answer real questions. I feel as if the current crop of physicists look down on things that appear too simplistic. Their math give an answer with artefacts they can’t match to reality so they keep probing the outliers of these absolutely bonkers ideas, and rabbit holes keep getting deeper & weirder. Time doesn’t exist. Do the people writing this garbage live in a vacuum? Is it AI slop?
- luc4sdreyer 9mo ago> Time doesn’t exist. Do the people writing this garbage live in a vacuum? Is it AI slop? Maybe don't dismiss an idea as garbage before trying to understand it. One of the ideas here is that time is an emergent phenomenon, like how temperature and gas pressure seem real at a macroscopic level, but disappear once you look closer. They simply describe the average kinetic energy of all the molecules in the area. The _hypothesis_ is that time could be similar.