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Universe sandbox 2 reddit8/10/2023 ![]() I tinkered around more with the simulation. An asteroid that's solid iron can orbit much closer than one that's made up of gravel loosely bound together by gravity. They also depend on the composition of the orbiting body and how well that material can handle tidal stress. Of course, Roche Limits aren't fixed boundaries. Its already equivalent to the fragments that break off the larger moons. Deimos didn't start breaking up though, so if you're using something like that as your minor moons, then it's possible the simulation can't break it into smaller pieces due to resolution issues. I put Mimas a little closer and it took longer for it to break apart, but within a few days its orbit was full of fragments and it was obviously shedding mass. Just tested it out by placing Luna way too close to Earth and it shattered pretty fast. Universe sandbox does include Roche Limits. And for very small moons, chemical cohesion can help hold them together even inside their roche limit. A given planet will have different roche limits for moons made of ice, rock, or metal. Roche limit is not a single value, but depends on both the density and physical nature of the orbiting body. Especially in tightly packed systems, other bodies will perturb that orbit, and the moon has to be closer to the planet such that these influences become negligible compared to the gravity of the planet. The Hill sphere is the rough area within which the planet's gravity dominates over the star, which is enough to cause a body to orbit the planet, but not enough for a stable orbit. There's also some nuance to what Hill sphere and roche limit are. I honestly wouldn't recommend using his math except for fairly earthlike planets orbiting fairly Earthlike stars. So whose side should I take? Universe Sandbox 2 with its seemingly complex and realistic math, or the more simple spreadsheet?Īrtifexian's math involves a lot of simplifications that may not hold up under the more complex simulation of US2. And if I place a minor moon ridiculously close (21 000km from the centre of the planet) it seems to be stable. If I try to place the major moon anywhere further than roughly 140 000km, it is ejected from the planetary system. This does not translate into Universe Sandbox at all, however. The most problematic being the Hill Sphere and the Roche Limit.Īccording to the spreadsheet, my planet (m=5 earth masses r=2 earth radii) that orbits around a red dwarf (M=0,3 solar masses) has a Hill sphere of about 80 Earth radii (around 508 000 km), while the Roche limit sits at around 4,8 Earth radii (30 000 km). The problem is that what the spreadsheet says doesn't align with what happens when I put everything that -seems to be checking out- into Universe Sandbox 2. Using Artifexian's brilliant tutorials, I've constructed a spreadsheet that gives me all I need to know. I've been trying to construct a rather complex planetary system, with a Super Earth, one major moon and six other minor moons. We also encourage users to register an account. (#worldbuilding on :6667, or 6697 for SSL) Looking for more active discussion? We have live chat communities that are active just about 24/7! Make sure to read the chat rules first Discord Server Snoonet IRC Channel There is also a curated list of resources compiled via Discord. Remember to check out the wiki for lots of resources and tips on starting out! Unsure why context is important? Consider reading our Why Context? essay. Full Subreddit Rules Modmail ResourcesĮvery post needs context! Consider using our context template to get started. We have high standards for on-topicness, respect of other people and respect for creative effort. ![]() This subreddit is about sharing your worlds, discovering the creations of others, and discussing the many aspects of creating new universes. For artists, writers, gamemasters, musicians, programmers, philosophers and scientists alike! The creation of new worlds and new universes has long been a key element of speculative fiction, from the fantasy works of Tolkien, Le Guin and Howard, to the science-fiction universes of Burroughs, Delany and Asimov, and to the tabletop realm of Gygax, Barker and Greenwood, and beyond.
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