Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid
These are organized by a classification scheme developed exclusively for Cosma. More…
Oort cloud, named after the Dutch astronomer Jan Oort, sometimes called the Öpik–Oort cloud, is a theoretical cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from 50,000 to 200,000 AU (0.8 to 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.
Astronomers conjecture that the matter composing the Oort cloud formed closer to the Sun and was scattered far into space by the gravitational effects of the giant planets early in the Solar System’s evolution. Although no confirmed direct observations of the Oort cloud have been made, it may be the source of all long-period and Halley-type comets entering the inner Solar System, and many of the centaurs and Jupiter-family comets as well.
The existence of the Oort cloud was first postulated by Estonian astronomer Ernst Öpik in 1932. — Wikipedia
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
Oort clouds around other stars should be visible...
on August 16, 2018 at 2:52 pm
For decades, scientists have theorized that beyond the edge of the solar system, at a distance of up to 50,000 AU (0.79 ly) from the sun, there lies a massive cloud of icy planetesimals known as the Oort Cloud. Named in honor of Dutch astronomer Jan Oort, this cloud is believed to be where long-term comets originate from. However, to date, no direct evidence has been provided to confirm the Oort Cloud's existence. […]
Comet C/2016 R2 (Pan-STARRS) is rich in carbon...
on May 30, 2018 at 1:10 pm
C/2016 R2 (Pan-STARRS) is a comet abundant in carbon monoxide and lacking hydrogen cyanide, according to a new study conducted by researchers from the University of South Florida (USF) in Tampa, Florida. The finding is detailed in a paper published May 17 on the arXiv pre-print repository. […]
Evidence that a star disturbed prehistory solar...
on March 21, 2018 at 9:50 am
About 70,000 years ago, during human occupation of the planet, a small, reddish star approached our solar system and gravitationally disturbed comets and asteroids. Astronomers from the Complutense University of Madrid and the University of Cambridge have verified that the movement of some of these objects is still marked by that stellar encounter. […]
The three surprises of 'Oumuamua
on February 5, 2018 at 2:41 pm
One of the defining moments in planetary astronomy in 2017 is that this is the year we discovered the first astronomical object to enter the Solar System from interstellar space. Now known as `Oumuamua (Hawaiian for "scout"), the object was discovered by the Pan-STARRS survey team in Hawaii on October 19th. Over the next three weeks it was in turn classified as a comet, a long-period asteroid and finally, the first of the new class of interstellar objects. […]
Extra-terrestrial Hypatia stone rattles solar...
on January 9, 2018 at 2:55 pm
In 2013, researchers announced that a pebble found in south-west Egypt, was definitely not from Earth. By 2015, other research teams had announced that the 'Hypatia' stone was not part of any known types of meteorite or comet, based on noble gas and nuclear probe analyses. […]