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.
Missing-link in planet evolution found
on January 28, 2019 at 4:00 pm
For the first time ever, astronomers have detected a 1.3 km radius body at the edge of the solar system. Kilometer-sized bodies like the one discovered have been predicted to exist for more than 70 years. These objects acted as an important step in the planet formation process between small initial amalgamations of dust and ice and the planets we see today. […]
Interstellar objects like 'Oumuamua probably...
on January 11, 2019 at 1:17 pm
On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) in Hawaii announced the first-ever detection of an interstellar object, named 1I/2017 U1 (aka. 'Oumuamua). In the months that followed, multiple follow-up observations were conducted to learn more about this visitor, as well as resolve the dispute about whether it was a comet and an asteroid. […]
We have a Christmas comet: How to spot...
on December 13, 2018 at 1:10 pm
We're in for a pre-Christmas treat this weekend, as the cosmos entertains us with two equally exciting gifts: the Geminid meteor shower and the interplanetary comet 46P/Wirtanen. […]
NASA's Voyager 2 probe enters interstellar space
on December 10, 2018 at 3:50 pm
For the second time in history, a human-made object has reached the space between the stars. NASA's Voyager 2 probe now has exited the heliosphere – the protective bubble of particles and magnetic fields created by the Sun. […]
Astrophysicist contributed into...
on October 18, 2018 at 4:10 pm
Evgenij Zubko of Far Eastern Federal University (FEFU), in collaboration with international team members, has developed a comprehensive model to explain the results of the recent photometric study of the comet Schwassmann-Wachmann 1 (29P). The surprising findings revealed that the dust environment of 29P predominantly consists of only one type of material—magnesium-rich silicate particles with presumably a small amount of iron (Fe-Mg silicates). […]