Oort cloud facts for kids

Relation of the Oort cloud to the solar system

Artist's idea of the Oort Cloud and the Kuiper Belt

The Oort cloud, or Öpik–Oort cloud, is a cloud of comets and other objects. Astronomers believe it is way beyond the orbits of Pluto and the Kuiper belt. The Oort cloud is believed to be the source of long-period comets in the Solar System.

The Oort cloud may lie about 50,000 AU, or nearly a light-year, from the Sun. This means the cloud is nearly a quarter of the way to Proxima Centauri, the nearest star to the Sun.

The Kuiper belt and scattered disc, the other two reservoirs of trans-Neptunian objects, are less than one thousandth of the Oort cloud's distance. The outer limit of the Oort cloud defines the boundary of the Solar System and the region of the Sun's gravitational dominance.

The Dutch astronomer Jan Hendrik Oort published the Oort cloud idea in 1950. The Oort cloud was named after him, as were the Oort comet, and Oort constants.

Structure

The Oort cloud takes up a lot of space and is thought to have trillions of comets about tens of millions of kilometers apart.

The Oort cloud is made up of an inner Oort cloud and an outer Oort cloud. The outer cloud is weakly bound to the Sun; long-term comets are thought to come from there. The Inner cloud is also called the Hills cloud and may be the maker of comets.

The objects in the Oort cloud are believed to consist of much ice. Since the object 1996 PW was found to be a rocky body in an orbit typical of long-period comets, it is believed that rocky objects might be in the Oort cloud.

Origins

The Oort cloud is thought to be the remains of a disk made out of gas which surrounded the Sun long ago.

The Solar System
Sun • Heliosphere	Planets ☾ = moon(s) ∅ = rings		Mercury	Venus	Earth ☾	Mars ☾
			Jupiter ☾ ∅	Saturn ☾ ∅	Uranus ☾ ∅	Neptune ☾ ∅
	Dwarf planets		Ceres	Pluto ☾	Haumea ☾	Makemake
			Eris ☾
	Small Solar System bodies	Asteroids (minor planets)	Groups and families: Vulcanoids · Near-Earth asteroids · Asteroid belt Jupiter Trojans · Centaurs · Neptune Trojans · Asteroid moons · Meteoroids · Pallas · Juno · Vesta · Hygiea · Interamnia · Europa
			See also the list of asteroids.
		Trans- Neptunians	Kuiper belt – Plutinos: Orcus · Ixion – Cubewanos: Varuna · Quaoar · Huya
			Scattered disc: Sedna
		Comets	Periodic comets and non-periodic comets Damocloids · Oort cloud
See also the list of solar system objects

Images for kids

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  Illustration of the Oort cloud

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  Artist's impression of the TAU spacecraft

See also

In Spanish: Nube de Oort para niños