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Author Topic: Incorrect simulation status  (Read 1916 times)


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Incorrect simulation status
« on: January 29, 2018, 03:28:30 PM »
I realize I shouldn't be too picky on literally one simulation in Universe Sandbox 2 in the first place but I might as well just for the fun of it. As many people know the 2018 January SuperBlueBloodMoon(Update maybe?) is coming up so I thought I'd look at this simulation "Solar System-Now&Real time" To see the moon inching ever so closer to the event on Universe Sandbox. However the simulation was completely disoriented with the moon on the completely other side of Earth.(OH NO) This only gives me reason to believe that practically every other object in this simulation is also incorrectly place.(except the sun of course)


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Re: Incorrect simulation status
« Reply #1 on: January 29, 2018, 03:58:16 PM »
Yeah, that is correct, because the planets aren't "on rails" so to speak. The simulation is done based on how the planets interact gravitationally and omputational error adds up greatly over time, plus some things aren't even taken into consideration yet that can make a difference like the non-use of General Relativity in US2 (GR will likely never be fully added using the proper equations for it but some things to "fake it" might be) so they haven't gotten to a system where gravity is simulated but the planets are where they are supposed to be too.


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Re: Incorrect simulation status
« Reply #2 on: January 29, 2018, 05:01:50 PM »
While there may be some errors due to accuracy over time, as Physics_Hacker suggested, these certainly wouldn't be enough to throw off the Moon that significantly in just a few simulated days.

I checked with our team and it appears our database information for the planets are correct in the "Now & Real Time" sim, but the Earth's Moon specifically seems to have an error somewhere that is setting its position in its orbit about a quarter farther than it should. So this is an error on our part, and not a fault of the simulation itself, or the fact that it is simulated. We'll look into this! Thanks for pointing it out.

Edit: We determined that all of the major moons are 90 degrees (1/4 of the orbit) farther than they should be, at least in that sim. We're looking into this to figure out where this error is happening. Thanks again for pointing it out. We appreciate having users who pay close attention!
« Last Edit: January 30, 2018, 01:08:52 PM by Jar »