The Oort cloud is a spherical cloud of comets and dust that extends three light-years from the Sun. It is theorized to have formed close to the sun but was ejected into huge parabolic orbits. It cannot be observed directly with telescopes.
The Oort cloud is a huge spherical cloud of comets and dust that extends three light-years from the Sun in all directions. The fact that the cloud is spherical rather than disk-shaped distinguishes it from other collections of debris in the solar system, such as asteroids and the Kuiper belts. The sphere is so large that its edge is closer to our nearest star than to the sun itself. The edges of the Oort cloud generally represent the limits of the sun’s gravitational influence: comets that stray too far from the edge become lost in space and become interstellar wanderers.
Almost every star is thought to have its own Oort cloud, of greater or lesser size. These clouds certainly overlap, and our sun’s Oort cloud probably overlaps the Alpha Centauri cloud. When the clouds overlap to the point that the edge of a foreign cloud envelops another star, an above-average frequency of comets will be seen within the central regions of that star’s solar system.
The Oort cloud was first theorized in 1950, when Jan Oort observed that there were no comets with orbits indicating that they came from outside the solar system, that there is a strong tendency for comet orbits to bring them up to 50,000 AU (50,000 times the distance between the earth and the sun), and that these comets arrive and depart randomly in all directions. This has led to the hypothesis of the Oort cloud, a cloud that cannot be observed directly with telescopes because the comets that compose it are too small and far apart. There are estimated to be about a trillion comets in the cloud, with a combined mass 100 times that of Earth. The Oort cloud objects are theorized to have actually formed relatively close to the sun, closer than the orbit of Neptune, but were ejected into huge parabolic orbits when they were hurled from the gravitational wells of huge planets like Jupiter.
Protect your devices with Threat Protection by NordVPN
