• @[email protected]
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    212 years ago

    I can’t wrap my head around time being anything other than the measurement of movement, and until someone can prove otherwise, that’s where I’ll be.

    • @[email protected]
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      112 years ago

      A definition I saw recently that I like is that time is the direction of entropy. You follow time one direction and you get the big bang where everything is chaotic and happening, and in the other direction you get the heat death of the universe, where everything has settled into a base state and nothing’s happening.

      • Hoptrain
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        32 years ago

        Do you mean, like reverse time? From my understanding of the concept of entropy, it strives to a maximum, meaning maximum disorder, by your definition the big bang.

        Or maybe do you have link where I can look into it? Sounds interesting

        • @[email protected]
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          12 years ago

          I wish I had a link, I think acollierastro talked about it briefly in one of her videos but I think it was a sidebar on something else so I have no idea which one. It was just one of those things where I heard the statement and it clicked on some weird intuitive level.

          I probably used “chaotic” inaccurately, but entropy strives towards maximum disorder in that there is energy holding things together and that energy won’t hold forever. The big bang was basically a big explosion where a whole lot of order was imposed on the universe, for example by forming particles, and since then there’s this general trend towards things falling apart. Energy can be used to fuse a particle, but left alone that particle will eventually fall apart, even if it’s not moving. That’s entropy. So time is that quantity where, given enough of it, things fall apart.

          Does that make sense? I have no idea if I’m explaining it properly, my physics background is super scattered.

          • @[email protected]
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            22 years ago

            Entropy is a measure of a number of distinct possible configurations that result in an equivalent outcome.

            It’s pure statistics. Given time symmetric laws of nature and a state that can be achieved by a relatively small number of configurations, in the absence of potential barriers, the system inevitably approaches a state that’s achievable by a larger number of configurations. Simply because an elementary change is more likely to fall into the latter mode. Thus, arrow of time emerges.

          • @[email protected]
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            22 years ago

            There seems to be a slight misunderstanding here: If you imagine the “moment before” the big bang that is a state where the entire universe is compressed into a singularity, which necessarily has no entropy, because it can only have one state. Once the universe started expanding, you get a whole lot of disorder, because, while you are forming particles (introducing order) those particles are moving away from each other at relativistic speeds. The available volume for the particles (the volume of the universe) increases extremely rapidly, meaning you have more possible microstates than if all particles were compressed into a point.

      • @[email protected]
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        22 years ago

        entropy

        To me that’s more of an emergent property of large numbers of particles moving from higher to lower energy states. Like temperature is just the velocity of an atom when you have lots of atoms moving and interacting.

        • @[email protected]
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          12 years ago

          I’m not sure that’s quite right in the sense that entropy is still meaningful on the level of individual particles—phenomena like proton decay, for example. But yeah, fundamentally it’s an emergent property from the way energy works, and on a grand scale that tendency is a way to view time.

          • @[email protected]
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            22 years ago

            proton decay

            A proton isn’t an individual particle but made up of quarks. If a proton decays (which hasn’t been observed) it’s still a transition from its component quarks to lower energy particles.

    • @[email protected]
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      92 years ago

      I’m going to take your definition just a step further and say it’s a measurement of causality specifically.

  • @[email protected]
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    92 years ago

    Shit’s on fire, yo. But does that fire only produce positive vibes or are there like 90% bad vibes, you know, bro?

  • qyron
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    882 years ago

    So, basically, we don’t know that much on anything besides understanding it’s really complex and difficult to figure out.

    • @[email protected]
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      112 years ago

      Not really. It’s all about models - we have for normal stuff, but it breaks apart in extreme situations

      So clearly the model is fundamentally wrong… Which is pretty cool, because it means FTL travel, antigravity, or travel between dimensions could be possible

      But we know now normal shit acts - we have models that work perfectly for 99% of all situations, and we’re probably not going to stop using them. We understand what happens when you throw an object, and it’s a basic equation up until like mock-2 or 3, where our models stop working and we have to switch them out completely

      Can you build a model that works for both? Absolutely. It’ll be closer to the truth even. But it’ll be way more complicated for nearly all practical, human scale situations

      At the end of the day, a model that describes reality exactly is almost useless… Without simplifications to ignore everything not relevant, just trying shit live would be easier than calculating the prediction

      • @[email protected]
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        12 years ago

        What I don’t understand is if the goal is to eventually be able to model everything perfectly, if we achieve that goal, doesn’t that just mean entropy is a lie?

          • @[email protected]
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            12 years ago

            Maybe it’s not a well thought out idea… But to me, if you can accurately model to predict everything down to the subatomic levels then where is the entropy?

            Maybe I don’t understand the basis of entropy.

            • @[email protected]
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              22 years ago

              I’m not sure how to answer exactly, so here’s a brain dump of my understanding of entropy

              Entropy is basically the tendency of energy to equalize into a lower energy state, converting a portion of the difference into heat, a portion of which escapes into the universe. It’s a statistical thing - it’s a general tendency that becomes predictable at the huge number of particles involved in anything near the human scale. Like compressed air - every atom is moving at a certain speed in a random direction (we model this with temperature)

              If you pop a balloon, the air rushes out because there’s more stuff to bounce off in the area of the balloon being popped, and less in the less dense surroundings. So, on average, the air bounces outwards, and the pressure (another model describing density + kinetic energy) equalizes.

              Now, if you have liquid air that is being actively cooled, air molecules bouncing in are going to transfer energy into the liquid, and be captured. The liquid is also going to heat up a bit, and the hotter it is, the more molecules are going to fly out. We usually model this with temperature + pressure, but gravity plays a big role too.

              So normally, entropy likes to average things out and prefers randomness - it applies to all sorts of things, like how potential chemical energy likes to be released into kinetic energy over time.

              But then look at the Earth - we have pressure waves in the air constantly. We say that’s because energy is being added to the system via heat from the sun, and it can even create these systems that turn these pressure waves into vortexes that can make ice in a hot place

              And then you look at stars - diffusion finally clicked for me after I sat in on a physics class explaining pulsars. They pulse out through this random diffusion, then pulse in due to gravity pulling them back in.

              Then we can look even further - stars pour out energy through fusion, and scatter themselves far and wide, seeding the next generation of stars. We thought that was just the initial energy of the big bang converting to lower energy states, but then you have dark matter and energy that we invented to explain the gap in the models… Now we think maybe the laws of physics might be less universal than we thought, or maybe higher dimensions are interacting with the universe

              Entropy is just another model - things generally transition to lower energy states, and convert their energy to heat… But there’s endless cycles that do the opposite. Entropy is a pretty compelling tendency in a closed system, but those don’t actually exist - it could be that there’re larger and larger cycles that oscillate between local entropy and the generation of local regions of higher energy

              Entropy doesn’t disappear if we can nail it down the subatomic - it’s just statistical behavior of. It might disappear if we go the other direction - what if every black hole spawns a new universe? Can you just go down the rabbit hole infinitely, creating smaller and smaller energy differentials through new universes? Maybe if we get deeper into quantum mechanics we’ll find that infrared energy spontaneously transitions into hydrogen, which forms into new stars, keeping the cycle going forever

              Entropy is a very useful model though, maybe it disappears over large enough scales, but ultimately it most certainly exists on a local level - complex, dynamic things will break down to form simpler things, and energy temporarily reverses this process, but in doing so a portion is converted to heat, and a differential is required to turn heat energy into something more complex like electricity or chemical energy

              So practically, I’d say the answer to your question is no, entropy is a very useful model regardless of what more we might learn, but in a truer sense who knows? We don’t understand physics nearly as well as we think.

              I think there’s a new wave of physics that will break a lot of our assumptions over the coming decades - we’re finding more and more gaps in our models, which is a very exciting thing

            • Natanael
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              2 years ago

              The trick is that the more closely you model things the more energy you need to expend to compute the model, and a computer can not perfectly model itself (it’s a data compression limit + zeno-like process overhead), so therefore you still increase unmodeled unknown entropy somewhere even if you have one closed system carefully controlled

    • MxM111
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      22 years ago

      Actually, we know everything there is happening in solar system. What we don’t know requires energies or distances or times incomparable with human life.

      • @[email protected]
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        72 years ago

        No it hasn’t. Many religions and spiritual texts covered all this stuff in just a couple of pages.

        • Flying SquidM
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          292 years ago

          Please do show the spiritual texts which cover general and specific relativity.

          • @[email protected]
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            32 years ago

            Deal if you show me the scientific texts that covered these in 500bc since you think we’ve always know how complex this is.

            • Flying SquidM
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              32 years ago

              I never made that claim, so how can I show you something I never claimed in the first place?

            • XIN
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              52 years ago

              If your point was that religions have oversimplified complex science to the point that people thought they fully grasped it, then I agree with you. Otherwise I have no idea what you are trying to say.

          • no banana
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            2 years ago

            The Bible says something about the earth and how it is good and the filament of the sky and something. The Bible that is, at least that’s what I read on the internet. Many fine people on the internet, the best people, but not me, I haven’t said it, but the best people probably. The best people say the earth may be - and I’m not saying it is but they are saying it - they say that the earth may be flat and that doesn’t take much text to cover I have heard.

          • MxM111
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            52 years ago

            You are missing the point. The creation myths were considered complete. Nothing left to be known.

            • Flying SquidM
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              92 years ago

              Well yes, people who believe things that aren’t true won’t admit that they don’t know anything. I’m not sure why that’s relevant though.

              • no banana
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                2 years ago

                I think their actual point was that incomplete explanations are nonetheless explanations. Still wrong though.

              • MxM111
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                32 years ago

                You stated “this has been always true” to the statement that we have understanding that things are really complex and difficult to figure out. The answer to you was an example that there were times where we did not have such understanding.

              • flatearth
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                2 years ago

                Material things are way below what God planned for man.
                Man (Body + Soul) was meant to be like God (NB God is not material) (in a good way).
                The Bible is not meant to be a physics textbook.
                Nevertheless, God owns everything. So things were talked about here and there…

                • @[email protected]
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                  52 years ago

                  The Bible also isn’t meant to be real. It’s a compendium of stories all put into one book, with tons of different writers. It’s akin to The Odyssey and shouldn’t be taken literally. Zeus didn’t come to Earth as a golden shower to impregnate Danae, and Jesus didn’t come back from the dead. They’re just fables.

          • @[email protected]
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            132 years ago

            If you squint a little, the 7 days of creation in Genesis are relativistic-ish. 1 day to separate light from darkness (photons at 1 microsecond after Big Bang), another to create the sky (opaque universe at 370k years), another to form dry land and create life (earth formed, 9.3 billion years, life at ~0.2by later), etc etc. Anyone with a physics degree able to say what fraction of light speed god must have been travelling to make this happen such that only days passed for them between these events?

            • flatearth
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              02 years ago

              They are literal days.
              Our God is King of leading by example.
              Also, man was made from the dust of the earth. It was fitting that earth be created before man (also very important for prideful man).
              As He did, so we must do.
              It is repeated constantly that we have 6 days to work, the 7th to be set apart.
              Why?

              • @[email protected]
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                32 years ago

                Rabbinical scholars argue about the correct translation of Genesis to this day. So you saying they’re “literal days” is meaningless.

                • flatearth
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                  2 years ago

                  They are literal days but also have mystical signification.
                  E.g. The sea (of our earth) can signify worldly people.
                  Rock can signify Christ.
                  The sun sometimes can signify Christ.
                  Stars, candles, salt can signify Christians.
                  Jerusalem can signify a place.
                  Babylon can signify a place.
                  Babylon can signify Antichrist.
                  All the examples above are different interpretations amongst 4 kinds of interpretation.

                  1. Literal (History is found here. Make sure they don’t contradict. Make sure they are not exclusive).
                  2. Moral (you can derive many).
                  3. Mystical (etc.)
                  4. Anagogical (etc.)

                  Before an interpretation is declared to be held universally, theologians can argue.
                  A new modern rabbi can even say that 7 days is 2 days and we will begin to argue.
                  Now we have AI image generation. If something about God is difficult for you, you can think of modern inventions.
                  Theory of evolution by Darwin and others is surely rabbinically modern.
                  God chose to create man on the 6th day (days are equally marked), and rest on the seventh.
                  The sun marks the day for us.
                  The moon marks the season/month.
                  Stars mark the year.

                  All these are what helped us arrive at our Gregorian calendar.
                  If you want me to read your source, please post a link to the rabbinical scholars, because money is capable of damaging a long standing tradition.

                • flatearth
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                  2 years ago

                  Rabbinical scholars don’t believe many things now:
                  Then, they believed the prophecy of Daniel and Herod even inquired from them (Herod did not want a rival king, so he ordered all new born infants to be killed. That was why Jesus, Mary and Joseph took refuge in Egypt).
                  Rabbinical scholars of now don’t believe in Jesus Christ, and what do you want God to do to them?
                  Rabbinical scholars of now don’t believe in Jesus Christ, and you expect me to believe rabbinical scholars?

                  Exodus 31:16,17
                  Let the children of Israel keep the Sabbath, and celebrate it in their generations. It is an everlasting covenant between me and the children of Israel, and a sign perpetual. For in six days the Lord made heaven and earth, and in the seventh he ceased from work.

                  Genesis 2:7
                  Our Lord God therefore formed man of the slime of the earth: and breathed into his face the breath of life, & man became a living soul.
                  [My comment] Not because Adam was difficult to make.

                  Genesis 2:22
                  And our Lord God built the rib which he took of Adam into a woman, & brought her to Adam.
                  [My comment] Wo + man = woman.

      • @[email protected]
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        2 years ago

        No, before the scientific method was invented, the religious consensus was that “All is known”.

        • veroxii
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          42 years ago

          “It’s all written down in this here book.”

        • @[email protected]
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          32 years ago

          And Aristotle was worshipped to the point where if people knew from personal experience that something he said was wrong, they’d assume their own experience was what was mistaken. And this despite him not having any connection to their religion at all.

          One example is that they used to think that objects could only have one force acting on it at a time. This could be the “natural force”, which is what makes objects fall when you drop them, or forces resulting from an action being performed on it. As a result, projectiles would travel straight in the direction they were thrown until the natural force took over, at which point they would fall vertically. Somehow this was still popularly believed (by academics at least) well after the catapult had been invented and used in sieges for centuries. It was believed by people who could throw things and observe how they moved with their own eyes.

      • qyron
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        762 years ago

        To quote someone a lot wiser than myself:

        It’s a shame stupid people carry themselves through life full of certainty while the wise ones suffer a life of doubt.

        • @[email protected]
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          52 years ago

          That’s a paraphrase of a famous Bertrand Russell quote. The original is as follows; “The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt.”

          There’s also the William Butler Yeats corollary; “The best lack all conviction, while the worst are full of passionate intensity.”

    • @[email protected]
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      2 years ago

      Not really, OP’s image is somewhat misleading. The truth is that we’re constantly trying to improve our understanding of physics and some theories are not completely correct but they often provide a way for future scientists to dig deeper and figure it out. Then with new knowledge, new hypothesis can be suggested creating a gateway to deeper understanding of some concepts further down the timeline.

  • @[email protected]
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    512 years ago

    I highly recommend the book “We Have No Idea” by Jorge Cham and Daniel Whitesom. Great explanations of what we know about the universe (with hilarious comic illustrations) and a profound message of just how much we don’t know.

    • @[email protected]
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      2 years ago

      Thanks for this recommendation! I love books that show me how little I truly know about anything.

      Like all of Randall Monroe’s books (xckd guy).

      Any more book recommendations?

      • @[email protected]
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        12 years ago

        I hope you enjoy it as much as I did! I’ve read it twice, apparently I needed to be reminded of how much I didn’t know. 😉

  • @[email protected]
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    2 years ago

    I think we got the fast stuff under control (special relativity), when you mix it it with like small stuff (quantum field theory), and I guess big stuff (general relativity), it is also OK, but mixing it with anything more than that causes a problem.

    • @[email protected]
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      22 years ago

      Just re-saw this episode a couple nights ago. It’s still the greatest episode of Doctor Who (It’s Season 3, Episode 10, Blink).

      Great science fiction. Great closed-loop time travel. Great horror. Everything that makes Doctor Who great.

  • @[email protected]
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    62 years ago

    I have been thinking that is impossible for ANYTHING to understand EVERYTHING. Because ANYTHING will always be a part of EVERYTHING, and you need EVERYTHING to understand EVERYTHING.

    Any system will always be a sub-system of some other system.

    Also I’ve been thinking about something I read: “The more close or deep we see, the more it seems to be nothing there”. I think it was related to subatomic particles, which seems to be just fields of energy instead of matter or something like that.

    I’d appreciate if someone wants to share a few comments or thoughts about this with me.

  • @[email protected]
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    92 years ago

    This is from science abridged beyond the point of usefulness right? I have that book.

    Edit: yes it is