Title text:

Unstoppable force-carrying particles can’t interact with immovable matter by definition.

Transcript:

[An arrow pointing to the right and a trapezoid are labeled as ‘Unstoppable Force’ and ‘Immovable Object’ respectively.]
[The arrow is shown as entering the trapezoid from the left and the part of it in said trapezoid is coloured gray.]
[The arrow is shown as leaving the trapezoid to the right and is coloured black.]
[Caption below the panel:] I don’t see why people find this scenario to be tricky.

Source: https://xkcd.com/3084/

explainxkcd for #3084

  • Hamartiogonic@sopuli.xyzEnglish
    141·
    6 days ago

    Maybe the universe will crash due to division by zero, floating-point error, integer overflow and segmentation fault, all of them occurring simultaneously. The objects will experience infinite velocity and infinite forces, there will be rounding errors, the system will run out of RAM and storage space. The universal CPU will max out all threads, and run out of cooling capacity. The hardware catches fire, the entire universe immediately collapses into a singularity, resulting in a new big bang as the system reboots. Oh, and the log files are corrupted, so good luck troubleshooting that one.

    • gnufuu@infosec.pubEnglish
      101·
      6 days ago

      A popup will appear asking you to buy the “Extended Physics” DLC

    • Zwrt@lemmy.sdf.orgEnglish
      311·
      6 days ago

      Division by zero is just zero.

      Just think about it. You have 4 slices of pie and 0 people to eat any.

      How much pie did each of those no people eat. Clearly the answer is just 0.

      Education took us for absolute fools.

      • WolfLink@sh.itjust.worksEnglish
        9·
        6 days ago

        It’s just as true a statement to say each of those 0 people at a billion slices of pie.

        However, with these types of word problems, there’s usually the implication that the pie is now gone. There’s kind of a problem figuring out where the pie went when nobody ate any pie.

      • Hamartiogonic@sopuli.xyzEnglish
        7·
        6 days ago

        This one is a bit counterintuitive. My maths teacher explained it like this. Take a look at this graph. If you approach zero from the positive side, it looks like the line goes to infinity. If you approach zero from the negative side, it appears to go to negative infinity instead.

        Is it both, is it zero, is it all the values? The canonical answer is “undefined”. The value of y at x=0 doesn’t have a meaningful answer.

    • pyre@lemmy.worldEnglish
      6·
      6 days ago

      if people only bothered to think about things that exist (especially things that they think exist) we would probably go the way of the dodo. funnily enough that would prevent the dodos from going that way but whatever.

      I highly recommend watching the Vsauce video on supertasks—it’s a great video as expected from Vsauce but also ends on a great note about people and their tendency to think about things like this.

    • AA5B@lemmy.worldEnglish
      31·
      6 days ago

      Neutrinos are pretty close to an unstoppable force: they can pass right through the earth without being stopped.

      I believe this is an expectation of dark matter, to being even closer to an unstoppable force. Perhaps a reason we haven’t found it yet would a because we don’t have a detector that can stop it

    • SmokeyDope@lemmy.worldEnglish
      2·
      6 days ago

      There are some pretty close physical analogs that are fun to think about. You cant move a black hole by exerting physical force on it in the normal way so practically infinite gravity wells are like a immovable “object”, though if you’re sufficently nerdy enough you can cook some fun ways to harness its gravitational rotation into a kind of engine, or throw another black hole at it to create a big explosion and some gravitational waves which are like a kind of unstoppable force moving at the speed of light.

    • Hamartiogonic@sopuli.xyzEnglish
      1·
      6 days ago

      These kinds of contradicitons exist in man made structures, such as laws, rules and regulations. In situations like that, a judge has to pick which rule to follow and which one to ignore. The first time that happens, it becomes the standard solution (precedent) for those kinds of problems.

  • jsomae@lemmy.mlEnglish
    11·
    5 days ago

    Ugh. This is a good point. Force = energy, and even an immovable object can carry energy. I assume.

  • argarath@lemmy.worldEnglish
    22·
    6 days ago

    Dammit I should have posted my exact same solution back when I thought of it for the first time, but I was lazy so eh my fuck up

  • dryfter@lemm.eeEnglish
    01·
    7 days ago

    I’m driving. I lose my brakes and can’t slow down as if my gas pedal is stuck (unstoppable force). I’m on a road that stops at a T intersection and there’s a concrete wall to keep people from going straight when they are moving vertically towards the T intersection (immovable object).

    The car just goes right through the concrete wall with no damage?

    Replace the concrete wall with a wooden fence. Technically the fence is immovable, but the car is going to smash right through that thing.

    So is this about clarifying what exactly the objects are? I’m not smart enough for this one and am so confused…

  • iAvicenna@lemmy.worldEnglish
    0·
    7 days ago

    so if god creates rock so heavy that it can’t lift it, its hand just passes through the rock? makes sense.

    • Gladaed@feddit.orgEnglish
      1·
      7 days ago

      A rock so heavy you cannot lift it is not an immovable object. Just cause you are weak does not mean you are right.

    • Cocodapuf@lemmy.worldEnglish
      0·
      7 days ago

      I think if God creates a rock so heavy he can’t lift it, it’s probably a black hole. By definition we can’t know what happens inside a black hole, because no information escapes the event horizon. As it’s now consistent with known physics that we can’t know many aspects of this interaction between God and the black hole, I think this paradox is basically solved. We don’t know any more about the interaction, but it’s no longer a paradox, it’s consistent with physics.

      • ripcord@lemmy.worldEnglish
        0·
        6 days ago

        But black holes have finite mass. By “heavy” you’re implying it’s infinitely heavy or something.

        You can definitely also lift a black hole.

        • Cocodapuf@lemmy.worldEnglish
          0·
          6 days ago

          Well I don’t know about any objects more massive than black holes. I think a black hole is really the only viable form a body can take once there’s enough matter in one place, like there’s an upper limit for the size of stars and after that anything larger collapses into a black hole.

          An object of infinite mass is a contradiction, a universe can’t exist with a single object of infinite mass, it would consume everything instantly.

          • ripcord@lemmy.worldEnglish
            1·
            6 days ago

            OK, but being very massive is not the same as what was being discussed.

            You can also “lift” a finitely massive black hole with anything else massive.

            • Cocodapuf@lemmy.worldEnglish
              1·
              5 days ago

              OK, but being very massive is not the same as what was being discussed.

              Are you sure? I mean the word “heavy” was what I was going on, but there is a distinction I suppose.

              You can also “lift” a finitely massive black hole with anything else massive.

              Yeah, that’s true… But again, I do have to stress that there is no alternative to “finitely massive” you really can’t have an object of infinite mass in our universe.

              Edit: So I guess it comes down to this: If “lift” and “move” are synonymous, then anyone can move any object of finite mass. An object of infinite mass can’t exist in this universe. So you could say that the answer to the question is definitively no, God can’t create a rock so big that he couldn’t lift it, at least not given the laws of physics in this universe as he created it. (For this conjecture we’re assuming God exists and created the universe).

              If God created this universe he could in theory also create other universes with different laws of physics. So in that case, sure, why not, who knows.

          • Snazz@lemmy.worldEnglish
            1·
            6 days ago

            It may be worth it to decide how we define ‘unstoppable force’ and ‘immovable object’.

            An Immovable Object has 0 velocity:

            v = 0

            Acceleration is the time derivative of velocity:

            a = d/dt(v(t))

            a = d/dt(0)

            a = 0

            And we know that

            a = Fnet / m

            An object with infinite mass would satisfy this equation, but an object with no net force would too. We could add a correction force that will satisfy the constraint of 0 net force.

            |Fnet| = 0

            ∑Fi = 0

            Fcorrection + … = 0

            To satisfy Newton’s 3rd law, we would need a reaction force to our correction force somewhere, but let’s not worry about that for now.

            A physics definition of ‘Unstoppable Force’ is:

            |Funstoppable| =/= 0

            In this case the gravitational force fits this description, given a few constraints

            Fg = Gm∑ Mi / xi2

            As long as the gravitational constant G is not 0, our object has mass, and

            ∑ Mi / xi2 =/= 0, then

            |Fg| > 0

            But this does feel kinda like cheating because it’s not really what people mean by ‘unstoppable force’. the other way to define it is just immovable object in a different reference frame.

            a = 0, |v| > 0

            I’m gonna stop here because this is annoying to type out on mobile

    • Saleh@feddit.orgEnglish
      0·
      7 days ago

      God is distinct from the creation and has no physical shape inside the creation so the idea of “object too heavy to lift” is already conceptually nonsensical.

      But also in the scope of our physics: What would an object be that is too heavy to “lift” for anyone and anything? It would be the heaviest object in the universe. So what will happen with the heaviest object in the universe? It would be the main center of gravity for everything else. In the same way you cannot “lift” the earth, but rather lift yourself from it as your force will just propel you away from the earth rather than the earth away from you, while you are inside the area dominated by earths gravitational field.

      • Cocodapuf@lemmy.worldEnglish
        1·
        7 days ago

        When you jump you are pushing the earth away from yourself a little bit, and then some of your gravity pulls the earth back toward you. You have moved the earth, and for a brief moment your jump has in fact altered Earth’s orbit.

        • Saleh@feddit.orgEnglish
          0·
          7 days ago

          Relative to the sun, which is the next center of gravity. As you go up the chain you end up with the heaviest object which you cannot move relative to anything, as it is the logical point of relative movement for everything else.

          • wolframhydroxide@sh.itjust.worksEnglish
            1·
            6 days ago

            Not relative to the sun, relative to momentum. Changes in the magnitude or direction of velocity are objective, not relative. These translate to real changes in momentum, from any reference frame. A real change in momentum is imparted upon the Earth roughly equal to your velocity relative to the earth multiplied by your mass at the moment your contact with the Earth ceases.

            ETA: I do actually agree with your salient point above: that lifting an object is relative to a given “down”, and so it is meaningless to expect to be able to “lift” the most massive object in the universe.

          • Cocodapuf@lemmy.worldEnglish
            1·
            7 days ago

            You need to be thinking about n-body physics though, everything affects everything. If the earth moves, that moves the sun a little, if the sun moves, that moves the local cluster a little, etc. Why wouldn’t that affect this heaviest object?

            I mean, are you suggesting that this heaviest object is simply the center of the universe and that all coordinates are defined around it? Because while that seems practical, I don’t think it’s how matter and space interact.

    • PlexSheep@infosec.pubEnglish
      0·
      7 days ago

      No that doesn’t make sense. The thing you’re alluring at is a classical thought experiment showing contradiction in allmightiness.

      P1: God is Almighty, meaning he can do anything

      Therefore he must be able to create a stone he can’t lift. But then there is something he can’t do: Either he can not lift the super stone, or he can not create a super stone that he can’t lift.

    • chatokun@lemmy.dbzer0.comEnglish
      1·
      6 days ago

      Two people can have the same idea. There’s even a term for it in science. Do you think Randall has watched every YouTube video that exists? I personally have never seen the video you linked, and while it has a decent amount of views, 13M over 12 years is pretty insignificant for other viral videos(for instance, nigahiga has multiple videos in the 30-60m range, and plenty more in the same 10-20m range like this video).

    • Piafraus@lemmy.worldEnglish
      1·
      6 days ago

      Force is not a thing that moves. Force is what is applied to an object. In this “answer” whatever is shown and depicted as force is not force.

      • AA5B@lemmy.worldEnglish
        1·
        6 days ago

        Then reverse the assumptions. Maybe it’s the immovable object that can’t be interacted with. Apply all the force you want and meet nothibg

        • Piafraus@lemmy.worldEnglish
          2·
          6 days ago

          If you applied the unstoppable force and the object of application did not move - then this force was not unstoppable

          • AA5B@lemmy.worldEnglish
            1·
            6 days ago

            Was that unstoppable force unstoppable before the object? Was it unstoppable after the object? Did anything stop it?

    • Ech@lemm.eeEnglish
      11·
      6 days ago

      Eh, it’s just redefining the assumed meaning. “Intangible” does mean “unstoppable” in a way, but that’s not really what’s intended.