![[solarSystem_sizes.svg|align:center|550]] ## Oort Cloud The **Oort Cloud** is distribution of [[Smaller Non-Planetary Bodies#Comet|comet]] nuclei stretching from beyond the [[Kuiper Belt]] subdivided into an inner [torus](https://en.wikipedia.org/wiki/Torus "Torus")-shape with a radius of $\sim 1,000 - 10,000\;{\rm AU}$ and an outer spherical shell with a radius of $\sim 10,000 - 100,000\;{\rm AU}$. > [!key-idea] **Important Characteristics:** > - Assumed no consistent velocity distribution or inclination in the orbits, contributing the the "cloud" structure > - Provides the source of long period comets in the solar system ($P > 200 \; {\rm yr}$) > - Formed from [[Planetary Migration#Planetesimal-Driven Migration]] (using icy [[Smaller Non-Planetary Bodies#Planetesimals|planetesimals]]) during [[Standard Model of Planetary Formation|Planetary Formation]]. > - Planets (mostly Jupiter) flung them out of the solar system, but not far enough to escape the Sun's gravitational attraction. > - The settled in the borderlands of the solar system, where the planets couldn’t perturb them anymore. > - Some of the captured bodies in the Oort cloud may not originate from our solar system, but its thought that majority come from [[Planetary Migration#Planetesimal-Driven Migration]] > - Some orbits have very high inclinations, and this could be caused by their initial scattering, galactic tides, or perturbations with other nearby stars.