Proposed reservoir · thousands to ~100,000 AU
Oort Cloud
A proposed distant reservoir of icy bodies, inferred mainly from the orbits of long-period comets.
The Oort Cloud has not been directly observed as a cloud. Its suggested inner edge is roughly 2,000–5,000 AU from the Sun; published estimates for its outer extent span tens of thousands of AU.
It is not drawn inside the planetary diagram: doing so would hide the enormous difference in scale. It is also distinct from the much closer, flatter Kuiper Belt.
Understand this region
The Kuiper Belt is not the Oort CloudSeparate the observed populations beyond Neptune from the much more distant proposed Oort Cloud, and compare what New Horizons learned at two targets. · 3 minFrom a nucleus to a coma and tailsFollow energy and material from an irregular comet nucleus into its surrounding gas and dust, using Rosetta’s observations of 67P. · 3 minThis proposed distant reservoir is not drawn at planetary scale. No individual object here is presented as a confirmed Oort Cloud member.
NASA · region reference ↗