The solar system is the combination of the sun and the astronomical objects bound to by gravity and all of which formed from the collapse of a giant molecular cloud around 4.6 billions years ago.There are many objects in the universe that orbit the sun and most of the mass is contained within eight relatively solitary planets whose orbit are almost circular and lie within a nearly flat disc which is called ecliptic plane.The four planets especially inner,Mercury,Venus,Earth and Mars are known as the terrestrial planets and they are primarily composed of rock and metal.Similarly the four outer planets, gas giant is the more massive than the terrestrials.The two big Jupiter and Saturn are made of hydrogeb and helium and the two outermost planets Uranus and Neptune are composed of ices like water,ammonia and methane and are also called ice giants.
Solar system is home for two regions populated by smaller objects.The asteroid belt which is in between Mars and Jupiter,is similar to the terrestrial planets as it is composed of rock and metal.The Neptune's orbit lie trans Neptune objects is composed mostly of such as water,ammonia and methane.Five individuals objects Ceres,Pluto,Haumea,Makemake and Eris are known to be large to have been rounded bu their own gravity within the two regions. They are also termed dwarf planets.In this two regions in the thousands of small bodies, various other small bodies populations like comets,centaurs and interplanetary dust freely move between these two regions.Humanity with the notable exceptions did not recognize the existence of solar system for many thousands years.People used to believe that the earth to be stationary at the center of the universe and different from the divine through the sky.
The main components of the solar system is the sun, a main sequence G3 which contains 99.86 percent of the system known mass and dominates it gravitationally.The sun's four largest orbiting bodies the gas giant account for 99 percent of the remaining mass with Jupiter and saturn together comprising more than 90 percent.The overall structure of the charted region of the solar system consists of the sun,four relatively small inner planets surrounded by a belt of rocky asteroids and four gas giants surrounded bu the outer Kuiper belt of icy objects.Sometimes the astronomers informally divided this structure into seperate structure.The inner solar system includes the four terrestrial planets and the main asteroid belt while the outer solar system includes the four gas giant planets which is beyond the asteroids.When the Kuiper belt is discovered, the outermost parts of the solar system are considered a distinct region which consists of the objects beyond Neptune.
According to the Kepler's laws of planetary motion the orbit of the objects or each object travels along an eclipse with the sun at one focus.Objects which are closer to sun move more quickly as they are more affected bu the sun's gravity.The orbit of the planet is nearly circular but many comment,asteroids and Kuiper belt object follow highly elliptical orbits.A body closet approach to the sun is known as perihelion and its most distant point from the sun is known as aphelion.Many representation of the solar system show orbit the same distance apart because of the vast distance involved.But with the few exceptions the farther a planet or belt is from the sun the larger the distance between it and previous orbit in reality.In the solae system, most of the planets possess secondary system of their own being orbited by planetary objects which is called natural satellites or moons or in the case of the four gas giants by planetary rings, thin bands of tiny particles that orbit them in unison.The inner solar system's objects are made of rock,the collective name for compounds with high melting points such as silicates,iron or nickel wich remained under the all conditions in protoplanetary nebula.Ices like water, methane,ammonia,hydrogen and carbon dioxide have melting points up to few hundreds kelvins while their phase depends on the ambient pressure and temperature. They can be found as ices,liquids or gases in various places in the solar system.
The Sun comprises all the matters in the solar system and it is composed of roughly 98 percent hydrogen and helium.similarly the Jupiter and Saturn that comprise nearly all the remaining matters possess atmospheres composed of roughly 99 percent of those same elements.A composition gradient,created by the heat and light pressure from the sun exists inthe solar system.The boundary in the solar system beyond which those volatile substances could condense is known as the frost line and it lies at roughly 4 AU from the Sun.