Solar System - 02
The most distant known body orbiting the Sun is the dwarf planet Eris, which was reported to have discovered in July 2005. Eris is currently about 97 AU from the Sun. Another planet like object in the outer solar system named Sedna is currently at 90 AU but will reach about 900 AU at the farthest point in its orbit, thousands of years from now. Comets known as long period comets, however, schieve the greatest distance from the Sun; they have highly eccentric orbits ranging out to 50,000 AU or more. A comet's period calculated as how long it takes to complete one revolution around the Sun. They are members of the Oort cloud, a spherial shell of comet nuclei that surrounds the flat plane of plabetary orbits at this enormous distance.
The Solar System is also home to two regions populated by smaller objects. The asteroid belt, which lies between Mars and Jupiter, similar to the terrestrial planets as it is composed mainly of rock and metal. Beyond Neptune's orbits lie trans-Neptunian objects composed most of ices, ammonia and methane. Within these two regions, five individual objects, Ceres, Pluto, Haumea, Makemake and Eris, termed dwarf planets have been revolving.
The Solar wind, a flow of plasma from the Sun, creates a bubble in the interstellar medium known as the heliosphere, which extends out to the edge of the scattered disck. The hypothetical Oort cloud, which acts as the sourse for long-period comets, may also exist at a distance roughly a thousand times further than the heliosphere. Six of the planets and three of the dwarf planets are orbited by natural satellites, usually termed 'moons' after Earth's Moon. Each of the outer plannets is encircled by planetary rings of dust and other particles.