- published: 26 Jun 2015
- views: 396896
The Oort cloud (/ˈɔːrt/ or /ˈʊərt/), sometimes called the Öpik–Oort cloud, is a theoretical cloud of predominantly icy planetesimals believed to surround the Sun to as far as somewhere between 50,000 and 200,000 AU (0.8 and 3.2 ly). It is divided into two regions: a disc-shaped inner Oort cloud (or Hills cloud) and a spherical outer Oort cloud. Both regions lie beyond the heliosphere and in interstellar space. The Kuiper belt and the scattered disc, the other two reservoirs of trans-Neptunian objects, are less than one thousandth as far from the Sun as the Oort cloud.
The outer limit of the Oort cloud defines the cosmographical boundary of the Solar System and the extent of the Sun's Hill sphere. The outer Oort cloud is only loosely bound to the Solar System, and thus is easily affected by the gravitational pull both of passing stars and of the Milky Way itself. These forces occasionally dislodge comets from their orbits within the cloud and send them toward the inner Solar System. Based on their orbits, most of the short-period comets may come from the scattered disc, but some may still have originated from the Oort cloud.
The Oort Cloud: Crash Course Astronomy #22
The Oort Cloud: Believe it or Not
How Far Away Is It - 2014 Update - Comets & Oort Cloud (1080p)
Where does the solar system end? A video about the Oort Cloud - Space Place in a Snap
7 facts about: OORT CLOUD
Phobium - Oort Cloud [Full Album]
Space Episode 10: The Oort cloud, The Kuiper Belt & The Biggest Thing In the Universe
"Oort Cloud" • Guitar Play Through • Chris Letchford
HOME - Oort Cloud
Nemesis and the Oort Cloud - The Sun's Evil Twin