An atlas of periodic solutions to the three-body problem

(threebodyorbits.com)

101 points | by danielmorozoff 2 days ago

10 comments

  • mr_mitm 3 minutes ago
    It's well organized, the animations are smooth, and it looks beautiful... I'm not sure what to do with the information, but it's mesmerizing and fascinating. Great find!
  • deskamess 1 hour ago
    I guess I misunderstood or mis-scoped the problem. Does the 3-body problem state 'the general case' has no solution, but that does not preclude some configurations from having a solution?
    • mr_mitm 0 minutes ago
      I'm pretty sure there is always a unique solution to the equations of motions (safe for some pathological edge cases perhaps). Classical mechanics is deterministic, after all. But for more than two bodies, there is in general no closed solution, and it's often chaotic, so not even computeable for arbitrary time frames.
    • layer8 25 minutes ago
      The three-body problem only states the problem to solve, it doesn’t itself state anything about the existence or non-existence of solutions. It has been proven that there is no general closed-form solution. And there are obvious solutions for trivial special cases, such as three equal masses in an equilateral triangle rotating around each other.

      Further reading: https://en.wikipedia.org/wiki/Three-body_problem#Solutions

    • Sharlin 19 minutes ago
      There is no closed-form solution for finding the roots of >4th degree polynomials in general, but that doesn’t preclude many families of >4th degree polynomials from having closed-form solutions. As a trivial example, x^5 - 1. The exact same thing with the three-body problem.
    • incognito124 1 hour ago
      That's exactly the case
      • isolli 1 hour ago
        It's also not computable, as in chaotic. Small differences in initial positions will lead to unpredictably large differences in trajectory (with small and large having specific meanings to match the formal definition of a chaotic system).
  • moritzwarhier 21 minutes ago
    Wow. This is really cool. Deterministic chaos is my absolute favorite in all the nerdy things there are to like in the abstract world.
  • inatreecrown2 1 hour ago
    Very cool visuals and site! Could I make a suggestion: You show the masses (1,1,1), but not the starting positions, which alter the course of events too.
  • RALaBarge 1 hour ago
    This is an amazing looking website, I like it a lot.
  • MeteorMarc 46 minutes ago
    I assume some of the solutions are stable against small perturbations, while others are not. That would be interesting to see.
    • summa_tech 46 minutes ago
      I think that's what "STABLE ONLY" clickable text filters by.
  • khalic 39 minutes ago
    I'm going to spend so much time on this website, very good work
  • IshKebab 35 minutes ago
    I assume this is at least partially vibe coded, but this is the first good vibe coded website I've seen. Amazing work.
  • RugnirViking 1 hour ago
    very ai but also pretty cool. wheres the data source? could I find my own periodic solution?
  • nautilus12 1 hour ago
    Is this assumed to be 2D? I was going to ask if there are any observed examples of 3 body equilibrium observed in nature.
    • raverbashing 1 hour ago
      Yes. Because 3 points are coplanar, so every "3D problem" with 3 objects can be turned into a 2D problem on the correspondent plane

      (of course in real life your plane would keep changing, and probably some other complicated math I can't think right now)

      • raincole 53 minutes ago
        Why would the plane keep changing? If there are only these three objects, won't the vectors of their gravitational pull to each other all be on this plane too?
        • hammock 23 minutes ago
          It’s an arbitrary plane, chosen at each moment just so you can flatten it
        • raverbashing 44 minutes ago
          Not from an external point of view, as you might have a momentum component perpendicular to that plane

          (but yes I think you might be right if we're centered on the CG)

          • twnettytwo 11 minutes ago
            One of the necessary conditions here is that the three objects return to their exact initial position, and so does the centre of mass. Initial conditions with non-zero momentum must trivially be ruled out. But this doesn't stop them from having velocities perpendicular to the initial plane that cancel out perfectly, so this doesn't refute the assertion that the planes keep changing.