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In the fundamental physics of the world, there is neither space nor time
- sanjay_ce 8y agoGGI_CONTEST #support_me_for_maximum #likes_share_views https://web.facebook.com/niraj.yadav.39108297/videos/2221393554772418/ https://web.facebook.com/niraj.yadav.39108297/videos/2221393...
- xvedejas 8y agoArticle: Spacetime is an illusion! Time isn't real! Reality: The details of time diverge a bit from common understanding. The author has an emotional reaction to this. Who else dislikes this sort of pop-science writing? It seems to care more about evoking some mystical and philosophical idea of the universe than effectively communicating the science.
- GW150914 8y agoI despise it, and it seems to have become all that Aeon is capable of. If I wanted to hear what a stoned Physics 101 student thought, I’d ask them. Good science isn’t necessarily sexy, it may not make for profitable clickbait, but it’s very rewarding. @Westoncb: Philosophy of science is about as useful to scientists as ornithology is to birds.
- westoncb 8y agoHmm... It's not from Aeon, and the author is a practicing theoretical physicist who also does work in history and philosophy of science—so about as well-suited to the topic at hand as you could get.
- danharaj 8y agoI'm sure for someone who has devoted his career to understanding spacetime, Rovelli's enthusiasm for the subject at least borders mysticism. The science of quantum gravity is wide open.
- sidlls 8y agoI devoted decades of my life to it and I never associated it with the borderline mysticism present in this article. It's all vectors, tensors, fields and operators, and the data which support certain models or provide avenues to yet more questions by exposing deficiencies and gaps. There's nothing deeper about it than that, except what we choose to apply for our own emotional satisfaction (which isn't unimportant, but certainly shouldn't be mistaken for truth in the world of physics).
- sixstringbudha 8y ago>It seems to care more about evoking some mystical and philosophical idea of the universe What is wrong about mystical, philosophical idea of the universe? I like mystical, philosophical idea of the universe.
- Koshkin 8y agoNothing wrong, just not science.
- sixstringbudha 8y agoEverything was "not science" before it became "science". So what is your point?
- deleted 8y ago[deleted]
- Koshkin 8y ago...if a thing is not a science, it is not necessarily bad. For example, love is not a science. So, if something is said not to be a science, it does not mean that there is something wrong with it; it just means that it is not a science. --R. Feynman
- sixstringbudha 8y agoDid quoting R.Feynman was part of your plan? Because I don't see no other point for your original comment other than to eventually quote R.Feynman. A: I like x B: I don't like x A: Why? B: Because it is not science A: Why is that bad? B: It is not. Because R.Feynman said blah blah blah... A: ??
- dgut 8y agoNothing wrong about it per se. Just don't try to mask it as or "soften" the principles of science.
- westoncb 8y agoI have a strong distaste for science popularizations that misrepresent results to make things seem more fun or exciting or whatever—but this isn't that. This is more a presentation of a physicist's worldview, giving some background on the physics which made it that way. > Reality: The details of time diverge a bit from common understanding. I think you may be underestimating the divergence a bit. The author is hardly alone in finding general relativity's implications on time to be of profound philosophical importance, for instance.
- lisper 8y agoYou may find this a little more to your liking: http://blog.rongarret.info/2014/10/parallel-universes-and-arrow-of-time.html http://blog.rongarret.info/2014/10/parallel-universes-and-ar...
- goombastic 8y ago>Who else dislikes this sort of pop-science writing? I love pop science writing. The thing is that this easy imagination helps a lot of people access hitherto unknowable principles of science. If you are science oriented or enquiry minded but do not have a background in the extreme detail required to access the specific subject/topic, you would have very likely never learnt anything about it given the arcane approach road to it. Popular science writing makes those spaces accessible, marks the roads, explains the possibilities and allows one to think through those abstractions. Then if you are sufficiently interested, you actually get into the hairy details of the actual science. But for most of us who are actually just traveling and understanding, this sort of writing gives us a grip of the "lay of the land." I look at such writing as maps of knowledge, not the actual thing, but sufficiently detailed and made interesting to give people a sense of where they are. It's a jungle gym for the thinking mind.
- ASipos 8y agoStrangely, Julian Barbour is never mentioned.
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- honorious 8y agoI just finished reading Rovelli's book "The Order of Time." The article is the last chapter, where the author summarizes the results of the "journey" of the book. I recommend the book, it was an enjoyable read. The author is able to explain clearly concepts that I had struggled to understand before. Throughout the book there are a many references to philosophical ideas and to the history of science, in some cases quite emotional. This being the last chapter, is quite heavy on them. However, I found them quite useful and interesting as a tool to break from preconceived notions of time.
- Koshkin 8y agoI think Sean Carroll has a point: http://www.preposterousuniverse.com/blog/2009/06/17/timelessness/ http://www.preposterousuniverse.com/blog/2009/06/17/timeless...
- honorious 8y agoIt might not be clear from the last chapter, but the book doesn't claim that time doesn't exist. To paraphrase (but use the same example because it is funny): time doesn't appear at the fundamental concepts in physics. Cats also don't appear at the fundamental level of physics. But cats exist. Time (and our perception of it) must appear somewhere as a emergent feature.
- sixstringbudha 8y ago>but the book doesn't claim that time doesn't exist. Why are people so hung up on the question whether 'x' exist or not without actually having a proper idea of what it mean for something to "exist"?
- adrianN 8y agoIt's surpisingly hard to define what it means for something to "exist".
- foxes 8y agoTime does appear in fundamental concepts in physics? In relativity it is particularly important. Timelike dimensions are treated differently in the metric, with a +1 or -1 depending on taste, ie ds^2 = c dt^2 - dx_1^2 - dx_2^2 - dx_3^2, so I don't think its quite fair to say that it doesn't "appear". In quantum physics unitary evolution is invertible. Decoherence is not reversible (I mean interaction - loss of entanglement). Maybe these theories have been biased by our perception, but they are good (but incomplete) models.
- TomMckenny 8y agoTime in relativity bears almost no resemblance to the common definition of time. 1) There is no such thing as simultaneous. There is no universal now. 2) Time does not proceed at a constant rate 3) Time proceeds at different speeds for different observers. So time as relativity defines it is certainly true. But time as people conceive it is fundamentally different. At best, common sense time is a profoundly special case that can't imagine the general case. And at worst, a nonsensical concept evolution gave us. Perhaps so erroneous it might be valid to say it does not exist.
- stephengillie 8y ago> Perhaps, ultimately, the emotional dimension of time is not the film of mist that prevents us from apprehending the nature of time objectively. Perhaps the emotion of time is precisely what time is for us. The application of sufficient Time and Space can solve almost any problem. If 2 groups are in conflict, putting 10 light years and 100 million calendar years between them often removes the ability to conflict.
- empath75 8y agoI'm starting to think that there's a point where physics becomes almost as much a study of our own mind as it is of the external world.
- Koshkin 8y agoThat has been said about mathematics, many times. But our minds are merely a reflection (often distorted, for that matter) of what's outside.
- bodi 8y agoMuch of the ancient esoteric wisdom taught that we were all of one, a mind, a singularity if you will. I think this bit of truth was purposely hidden, as Einstein himself alluded to, by a dark cabal, and has coincidentally been rediscovered albeit as a secular institution primarily through a diefication of the scientific process. Some of our still very early study of Quantum Mechanics points right to this matrix reality we experience. However uncomfortable that may be.
- blueprint 8y ago> The difference between past and future does not exist in the elementary equations that govern events in the world. Such bullshit. QM does not govern events. The probability function encodes everything about how it's governed. QM does not speak to that at all. Unitarity assumes the probability function remains correct. That doesn't mean the probability function does not have any inputs which can be influenced by change. Dumb article
- blueprint 8y agoLol downvoters don't even know the Copenhagen interpretation is deeply flawed and never learned to use their words
- zyxzevn 8y agoOur physical world is space and time, but in the maths of physics we lose track of it. ;-)
- v_lisivka 8y agoSome books about QM include big warning about "Mathematics is not Physics!" at very beginning, but nobody reads it. Chapter 2 The Formulation of Quantum Mechanics 2.1 Basic Theoretical Concepts Every physical theory involves some basic physical concepts, a mathemati- cal formalism, and set of correspondence rules which map the physical concepts onto the mathematical objects that represent them. The correspondence rules are first used to express a physical problem in mathematical terms. Once the mathematical version of the problem is formulated, it may be solved by purely mathematical techniques that need not have any physical interpretation. The formal solution is then translated back into the physical world by means of the correspondence rules. Sometimes this mapping between physical and mathematical objects is so obvious that we need not think about it. In classical mechanics the position of a particle (physical concept) is mapped onto a real number or a set of real numbers (mathematical concept). Although the notion of a real number in pure mathematics is not trivial, this correspondence rule can be grasped intuitively by most people, without any risk of confusion. The mathematical formalism of quantum mechanics is much more abstract and less intuitive than that of classical mechanics. The world does not appear to be made up of Hermi- tian operators and infinite-dimensional state vectors, and we must give careful and explicit attention to the correspondence rules that relate the abstract mathematical formalism to observable reality.
- neuralzen 8y agoCertainly makes sense if the holographic principle is correct, and our universe of experience is encoded in the entropic 2D planar surface of a blackhole.
- xaedes 8y agoWhat I don't understand about this idea: What is with all the other black holes? Are the holographic universes of each black hole the same? Do they encode the other black holes in their surface?
- jakeinspace 8y agoThe idea is that we are inside (or on the surface of, same thing) a black hole whose event horizon encompasses the entire universe (observed and unobserved). The black holes we can see in our universe would then be children black holes (or great-great-grandchildren, who knows how far down the holographic rabbit hole we are).
- yters 8y agoMakes sense. Everything can be encoded in a bitstring, which is a single number, and a single number has no sense of space and time.
- bodi 8y agoOne of the most beautiful and simultaneously terroristic traits of our existence is that of binary computational equivalence. Of course, binary as a notion is simply a set of relative measurements of the peaks and troughs of a wave at a specific time and scale, therefore we may deduce the ultimate excitation of all, what appears as this large number, is an analog, encompasses everything, and our reality a carefully crafted series of reductions from this source. Wonderful and awe inspiringly scary that we may even consider such a thing of brilliance.
- TheOtherHobbes 8y agoMany things can be approximately represented by a bitstring. Perhaps the difference between an approximation and a complete encoding should be emphasised more forcefully on CS courses.
- coffeeaddicted 8y agoThere are infinite recursive processes which can't be encoded in a bitstring. You can only put the results you got so far into one. To get more digits you will have to evaluate the function.
- pbhjpbhj 8y agoNot everything, but perhaps a description of most things.
- yters 8y agoIf reality is finite and discrete, then it is everything. On the other hand, if there are non computable processes at work in reality, then not everything.
- kr4 8y agoWe do have an easy way of doubting space/time real existence in form of dreams. In dream we feel sensation, experience space and time and it feels so real till the dream last. You can experience long hours or someone can experience years [0] within few seconds/minutes of a dream. Hence to take a next big leap in understanding the cosmos we as a society will eventually need to be bold enough and open for other ideas regarding the truth of objective reality we experience in waking state. Could it be just like a dream, though a grand one, being projected by some cosmic consciousness of which we are inseparable part? Not some divine form I'm proposing here, but a formless pure consciousness awareness that each of us possess and experience it in silence. Eastern mystical traditions have long been investigating these alternative ideas and countless individuals have testified experiencing such super conscious state confirming the idea.
- incompatible 8y agoI'm not sure about entropy arguments for explaining the direction of time. On Earth, the entropy doesn't change much over time, thanks to a constant stream of low-entropy in the form of radiation from the Sun. Overall, the system is increasing in entropy. But why do we, on Earth, need to care what happens in the Sun? We could just as well go backwards in time as forwards, but influencing the past seems to be extremely difficult (just try kicking a football backwards in time).
- dwaltrip 8y agoI believe the same reasoning applies here on Earth. Imagine a pile of ash (high entropy) assembling into a copy of Shakespeare (low entropy), compared with the reverse. You can get isolated pockets of low entropy that appear (e.g. the human brain), but I think I've heard it described that there has to be thermodynamic pathways leading to such states. We understand parts of these pathways, but there are important aspects still left to figure out. And of course, as you mentioned, the system as a whole is still increasing in entropy the entire time. Imagine a mountain where height inversely correlates with entropy. The summit represents the very low entropy state of the big bang, and the second law of thermodynamics is an enormous steam-roller that is currently in the process of flattening the entire mountain. Then, us humans are simply pebbles that have been shaken loose and are dancing in the foothills. In a few billion or trillion or quadrillion years, all the dancing pebbles will have been crushed into a fine dust and spread across a perfectly flat, unchanging plane. But they will have danced beautifully in the many years before.
- TomMckenny 8y ago> very low entropy state of the big bang This always confuses me a bit, why do we consider the first instants of the universe maximally ordered? A near homogeneous sea of per-subatomic particles seems less ordered than the later universe of galaxies and stars and hydrogen atoms with cold areas in between.
- sgt101 8y agoI tried to understand Roger Penrose's arguments about this in his book "Cycles of Time". I admit that I really struggled! But the idea seems to be that the initial state of the universe is very unusual compared with the rest of eternity and is essentially 1 vs nothing - and then differentiation instantaneously occurs through some physical process and immediately the universe can only be described in a complex way. The universe moved from undifferentiated high energy to and extremely complex high energy and then falls down from there back to flat. One point that seems not to feature in these debates is that this is all (physics) fundamentally subject to the constraints of language (maths) and cognition (human), we choose to describe things in a way that appears useful to us, but these judgements and perceptions are filtered by how we understand things. We are squashy and small and it is quite silly to imagine we really are thinking about these processes in an objectively meaningful way.
- combatentropy 8y ago> we have imagined the existence of "eternity," a strange world outside of time that we would like to be inhabited by gods, by a God, or by immortal souls If fundamentally there is no time, then fundamentally there is only eternity.
- stareatgoats 8y agoYes, I suspect (without further proof ATM) that this is the main reason for this quest for timelessness which Sean Carrol (cited in another comment) finds so perplexing [0]. Eternity has traditionally and in various ways been associated with (especially) monotheism. Same with infinity (of which eternity is a sort of subset). A much simpler but perhaps more tedious way out of this apparent rational loophole for religions would be accept it. Religion may keep this final straw of rationality: we don't and can't know everything given a (probably) infinite universe. Religion is not best understood as a theory of physics anyway, but rather as a study of history, society and mind. [0] http://www.preposterousuniverse.com/blog/2009/06/17/timelessness/ http://www.preposterousuniverse.com/blog/2009/06/17/timeless...
- JohnStrangeII 8y agoWhat loophole are you talking about? As much as I try, I cannot see any connection whatsoever between religion and concepts of infinity and eternity in physics. Is the idea that anything that science currently cannot explain must be connected to religion? That would be a fallacy.
- AltruisticGap 8y agoThe universe IS completely unknown, and forever will be. It is like a sandbox. As Alan Watts put it with his mischievous sense of humor: "Science is the art of prediction" Talking about religion, Christianity used to refer to this, then it lost its way. See eg. https://en.wikipedia.org/wiki/The_Cloud_of_Unknowing https://en.wikipedia.org/wiki/The_Cloud_of_Unknowing
- paganel 8y ago
- mirimir 8y agoMaybe so, but he also says ... > To this blurring is added quantum indeterminacy. The ignorance that follows from this determines the existence of a particular variable—thermal time—and of an entropy that quantifies our uncertainty. ... and ... > The variable “time” is one of many variables that describe the world. It is one of the variables of the gravitational field: At our scale, we do not register quantum fluctuations, hence it is possible to think of spacetime as determined. Hence we can think of spacetime as being as rigid as a table. This table has dimensions: the one that we call space, and the one along which entropy grows, called time. In our everyday life we move at low speeds in relation to the speed of light and so we do not perceive the discrepancies between the different proper times of different clocks, and the differences in speed at which time passes at different distances from a mass are too small for us to distinguish. But whatever, I am moved to read his book :)
- dschuetz 8y agoIt's rare to read from such a sober-minded yet deeply philosophical world view. He basically outlines to most essential things in the universe - gravity and uncertainty. Everything else is a means to quantify the world to make it more understandable to us. At least quantum mechanics show that uncertainty is quantifiable to an extent with the means we already have. I'm not even sure whether gravity is as un-quantifiable as it seems to be. That's what scientific minds ought to figure out.
- mannykannot 8y agoThere was a time when it seemed that science worked within the constraints of epistemology, but now it seems to be radically reshaping that domain.
- sunstone 8y agoIn which case it's obviously broken from the get go.