Is there any software tool for quickly prototyping a planetary system? Ideally this should:

  • Allow for placement of planets of different sizes and masses around a star.
  • Allow for examination of the interactions of the planets caused by gravity.
  • Allow for examination of day and night on the planets and eclipses.
  • 4
    $\begingroup$ It would help if you could specify an operating system, or specify cross-platform is needed/not needed. $\endgroup$ Oct 9, 2014 at 11:42
  • $\begingroup$ The operating system does not matter, as I can access computers with just about any system. $\endgroup$
    – Village
    Oct 9, 2014 at 23:02

4 Answers 4


There's Universe Sandbox, which while considered and marketed as a game and using some orbital calculation approaches that are outdated by modern astronomical standards, should work great for worldbuilding and simulating celestial bodies and events.

It's paid software, but it does allow you to simulate the Solar System, albeit without much accuracy very far into the future. The current version is Windows only, with the next one being made for OSX and Linux apparently. There's a free version but you can't add objects.

edit - Taemyr mentions that Universe Sandbox will not model day and night, so if you need that, you might have to look elsewhere or wing it.

edit - Having recently acquired and played Universe Sandbox, I want to add that while it's ok to use when you want to answer some abstract question ("What if Jupiter disappeared?") it really isn't very good for a realistic and detailed analysis (not to mention, it is quite buggy and not very fun). From what I gather, you really need to perform some simulations on a computational math package if you want something like that.

  • 2
    $\begingroup$ I will second this. Universe Sandbox is great for answering questions like: "What if the planet Earth just vanished?" or "What would happen if I had a planet orbiting a planet orbiting a planet?" And on top of all that, its just fun to kick back and annihilate some solar systems. $\endgroup$ Oct 9, 2014 at 12:15
  • $\begingroup$ It will not model day/night though. And I think it would be difficult to use for showing eclipses. $\endgroup$
    – Taemyr
    Oct 10, 2014 at 10:05
  • $\begingroup$ @Taemyr I haven't used it :P just knew it was around, but thanks for mentioning that, i'll add it to the answer. $\endgroup$
    – mechalynx
    Oct 10, 2014 at 10:06
  • $\begingroup$ Universe Sandbox is no longer maintained. The team has moved on to Universe Sandbox ² which does support night/day cycles. It is still alpha but very useable. $\endgroup$
    – Envite
    Nov 14, 2014 at 13:06

When I was in the university physics program I was given a Physics simulator package called CUPS, it contained many packages (electrodynamics, quantum mechanics, classical mechanics, and astrophysics).

The astrophysics package contained a planetary orbital dynamics simulator that would suit your requirements.

All of the CUPS packages came with PASCAL source code, so you should be able to run them on your favorite OS, if you can program in PASCAL


To some extent, you can create your own star system also in Space Engine. It has beatiful graphics, it allows you to make videos or photos from the surfaces of planets in various angles, but it is not so interactive as the Universe Sandbox. This basically means that you have to input the parameters in text format and you cannot just add them by clicking. The Space Engine is free.

I have also heard that AstroSynthesis is quite good, but I have no experience with it myself.

  • 1
    $\begingroup$ It should be noted that Space Engine is still very much in beta, but is being actively (if slowly) developed by one person. $\endgroup$
    – ajp15243
    Oct 9, 2014 at 18:30

My personal favorite is My Solar System, by the University of Colorado-Boulder. You can also access version 2.04 directly here.

It's pretty basic, but it has some cool features. You can choose to view from the perspective of the system's center of mass, of that of a hypothetical stationary observer. Other features include tracing orbits of the objects.

You can adjust a few different quantities:

  • Number of objects (up to 4)
  • Mass of objects
  • Position of objects
  • Velocity (magnitude and direction) of objects

These can give a pretty good description of a system of bodies. You can't model day and night, but you can satisfy your other criteria.

By the way, the system is free.


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