![]() Strange forces - Causes bodies to repel each other when they get too close. Toggles between normal and Modified Newtonian Dynamics (currently disabled) (effect is not obvious - the default mode is more accurate) Toggle between different calculation modes for particles/dust. Universe Sandbox 2 Free Download is a physics-based space simulator that allows you to create, destroy, and interact on an unimaginable scale. Set hi-res screenshot to 2x2, 4x4, or 5x5 (default is 3x3) Toggle movie record (multiple screenshots) Toggle drawing size of bodies (always visible or true to scale) Show / hide relationship lines (connects bodies with their gravitational parent) While holding down the key also press Shift or Ctrl to rotate on the other 2 primary axis. Hold down this key and move the cursor left or right to rotate the hovered body. Hold down this key and move the cursor to move the hovered body. This shows all movement of other bodies relative to the hovered body. Sets the radius of the body so that its escape velocity equals the speed of light (this is the Sch warzschild radius) ![]() Real Time (where 1 simulated sec = 1 real sec)Ĭhange the collision elasticity in bounce mode. Retarding gravity alone, without these other terms, seems to be the wrong thing to do in this case.Orbit All - forces all bodies to orbit their current gravitational parent I haven't tested this yet, but since this comes from a reliable source, I tend to believe it. I had thought so as well, but according to thoughtful answer this is probably not so. You can read more about these in Jenn's blog post: Gravitational Waves & Universe Sandbox². One example is setting gravity to travel at the speed of light, instead of instantaneously taking effect as it currently does. We are, however, interested in adding in a few features which would address some effects of relativity. That is, taking your simulation space, discretizing it to a hi-res 3-D grid and checking the effect that each and every point in that grid has on all neighboring points at every timestep" but just adding the major GR effects to the propagation of solar system bodies certainly doesn't need anything more than whatever computer you are already running your copy of Universe Sandbox 2 on already. Yes for Gravitational Waves, collapses, and other effects "requires simulating the spacetime itself. Using this straightforward approximation is much better than not using it in this context. The FAQ's suggestion that they don't do it because you need a supercomputer to be accurate is slightly misleading. ![]() Interaction between the Moon and Ceres for example could still be Newtonian.Īll approximations are approximate. To get close, you certainly don't need to evaluate these GR terms for every pair of objects. I reproduced what's normally done in Python rather than in a compiled language for transparancy, it would be much faster if included in a reasonable simulator implementation.Īs explained here, to the Newtonian acceleration given by: Why do I say this is not very satisfying or helpful?īecause it's quite easy to nearly completely account for General Relativity (GR) effects in the orbits of solar system bodies just by adding some terms to the ODEs that are integrated to propagate orbits.Īnswers to the question How to calculate the planets and moons beyond Newtons's gravitational force? (including mine) show how this is done all the time. You start with some initial data of the shape of your spacetime and then see how it evolves according to the Einstein equations, which are 10 highly non-linear partial differential equations." ![]() Instead of simulating N number of bodies, you are simulating a huge number of points. That is, taking your simulation space, discretizing it to a hi-res 3-D grid and checking the effect that each and every point in that grid has on all neighboring points at every timestep. Jenn, astrophysicist and Universe Sandbox² developer, explains more in a blog post: "General relativity requires simulating the spacetime itself. Why? The short answer is that you need a supercomputer to accurately simulate general relativity. Universe Sandbox is the next evolution of the original which we are actively updating. It laid the design groundwork for Universe Sandbox (which you also appear to own). No, the physics in Universe Sandbox² is currently only Newtonian. The original Universe Sandbox was updated over 30 times and released on Steam in April of 2011 (over 5 years ago). As noted by in this comment, the Universe Sandbox 2 FAQ addresses the question, but not in a satisfying or helpful way:
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