[Swordmaker]

I should point out that the current accept cosmology cannot fully account for why there is a plane of the ecliptic... or why the ringed planets have their rings exactly over their equators... gravity alone cannot account for it.

[SunkenCiv]

In the case of the planets, a single explosive event could account for it; I was thinking today about the supposed Oort cloud, which is said to look like this:

Mostly I regard the Oort cloud as a hypothetical construct made necessary by theory rather than detected through observation (iow, a kludge), but a spherical concentric cloud doesn't seem too likely -- although it might have got there (if it is found to exist) when an earlier version of the Sun blew up.