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Forum » SpaceEngine » Feedback and Suggestions » Have objects below a certain mass be non-spherical (or maybe a lumpy sphere, at best)
Have objects below a certain mass be non-spherical
smjjamesDate: Wednesday, 24.10.2012, 04:16 | Message # 1
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I don't know why I didn't take notice of this until now, but Marteks question about the smallest objects got me to realizing that the moons below a certain size shouldn't be spherical.

You see, we have in our system that are on both sides of the point where an object has enough mass to pull itself into a sphere, these are Ceres and Vesta. Ceres is spherical and Vesta is, well, sort of spherical, so the critical point is between them.

So, I'm just saying that for added realism, moons below maybe 0.0001 Earth mass (it's a total guess, I really don't know what the mass point would be, just that it's between Ceres and Vesta) should look like big lumpy asteroids.

The sort-of spherical asteroid models that SE has could be used for them, just with more detail maybe? Or maybe..... lumpy selena models?







Edited by smjjames - Wednesday, 24.10.2012, 04:23
 
WatsisnameDate: Wednesday, 24.10.2012, 08:38 | Message # 2
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Yes, what you are referring to is sometimes called the "Potato Radius", and depends on the object's size, density, and material strength. For rocky bodies (asteroids, dwarf planets) it's about 300 kilometers, and is lower for icy ones. smile






Edited by Watsisname - Wednesday, 24.10.2012, 08:42
 
smjjamesDate: Wednesday, 24.10.2012, 09:01 | Message # 3
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Actually, from what harb said on the other thread and the so called potato radius, maybe the settings in SE are actually fine? Space Engineer will probably clear this up since I didnt have a good understanding of what the potato radius limits were.

I mean I get it now what the general limits are, but earlier, I didn't know for sure about all that and was going by Vesta and Ceres.







Edited by smjjames - Wednesday, 24.10.2012, 09:03
 
HarbingerDawnDate: Wednesday, 24.10.2012, 09:32 | Message # 4
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Quote (Watsisname)
For rocky bodies (asteroids, dwarf planets) it's about 300 kilometers

Based on looking at Solar system objects, it's actually not that clear. The reference that is often used is that Ceres is spherical and Vesta is not, so therefore the boundary must lay between them. But that is not a good reference to use since Ceres' composition is more similar to an icy world than a rocky one (it is nearly the same density as Pluto, as well as other icy bodies comparable to its own size). So although a rocky/metallic body may be able to be a sphere at Ceres' size, we have no proof of this. As I said in the other thread, the smallest spherical rocky/metallic body in the Solar system is Europa, and the boundary almost certainly lays far below its size.





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WatsisnameDate: Wednesday, 24.10.2012, 15:49 | Message # 5
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HarbingerDawn, did you see the link I provided? It gives a fairly thorough derivation. smile




 
smjjamesDate: Wednesday, 24.10.2012, 15:57 | Message # 6
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Anyways, I think the way the tiny moons and moonlets look may actually be fine in SE since I didn't have a full understanding of how the potato radius mechanism worked, just a basic concept




 
SpaceEngineerDate: Wednesday, 24.10.2012, 16:39 | Message # 7
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In SE, boundary is passed at 6·10-6 Earth masses, that corresponds to a radius about 200-300 km (depending on composition).




 
Forum » SpaceEngine » Feedback and Suggestions » Have objects below a certain mass be non-spherical (or maybe a lumpy sphere, at best)
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