Solar System

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The Solar System consists of the Sun and those celestial objectsbound to it by gravity, all of which were formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago.
The four smaller inner planets, Mercury, Venus, Earth and Mars, also called the terrestrial planets, are primarily composed of rock and metal.
 The two largest, Jupiter and Saturn, are composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are composed largely of ices, such as water, ammonia and methane, and are often referred to separately as "ice giants".
The Solar System is also home to two regions populated by smaller objects.


Sun



The Sun is the star at the center of the Solar System. The Sun's color is white, although from the surface of the Earth it may appear yellow because of atmospheric scattering of blue light.The Sun is currently traveling through the Local Interstellar Cloud in the Local Bubblezone, within the inner rim of the Orion Arm of the Milky Way galaxy. The Sun is no more than a star and in 1 year the Sun can grow no more than 7cm or less. Is possible that a star can be much bigger than the sun. 


Planets 


Mercury



Mercury is the innermost and smallest planet in the Solar System.  Since Mercury is normally lost in the glare of the Sun, unless there is a solar eclipse, Mercury can be viewed only in morning or evening twilight. Mercury is similar in appearance to the Moon: it is heavily cratered with regions of smooth plains, has no natural satellites and no substantial atmosphere. Mercury’s surface is overall very similar in appearance to that of the Moon, showing extensivemare-like plains and heavy cratering, indicating that it has been geologically inactive for billions of years. 


Venus


        
Venus in real color                                 Global view of the surface (from Magellan     Impact craters on the surface of Venus       
                                                                             radar imaging)                                                 (image reconstructed from radar data)


Venus is the second planet from the Sun. Venus is classified as a terrestrial planet and it is sometimes called Earth's "sister planet" due to the similar size, gravity, and bulk composition. Venus is covered with an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space invisible light. Venus has the densest atmosphere of all the terrestrial planets in our solar system, consisting mostly of carbon dioxide. Venus has no carbon cycle to lock carbon back into rocks and surface features, nor does it seem to have any organic life to absorb it in biomass.


Earth



Earth  is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. Earth's outer surface is divided into several rigid segments, or tectonic plates, that migrate across the surface over periods of many millions of years. Earth interacts with other objects in space, especially the Sun and the Moon. The shape of the Earth is very close to that of an oblate spheroid, a sphere flattened along the axis from pole to pole such that there is a bulge around the equator. The Earth's terrain varies greatly from place to place. The Earth's atmosphere has no definite boundary, slowly becoming thinner and fading into outer space. Earth's rotation period relative to the Sun its mean solar day. The Earth is special from the other planets because it is the only Planet with life.


Mars 


      
Mars is the fourth planet from the Sun in the Solar System. Mars is a terrestrial planet with a thinatmosphere, having surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts, and polar ice caps of Earth. The rotational period and seasonal cycles of Mars are likewise similar to those of Earth. Mars is the site of Olympus Mons, the highest known mountain within the Solar System, and of Valles Marineris, the largest canyon. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. Mars can easily be seen from Earth with the naked eye. Mars has approximately half the radius of Earth. It is less dense than Earth. 


Mars


  
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. Jupiter is classified as a gas giant along with Saturn, Uranus and Neptune. Together, these four planets are sometimes referred to as the Jovian planets. Jupiter is primarily composed of hydrogen with a quarter of its mass being helium; it may also have a rocky core of heavier elements. Because of its rapid rotation, Jupiter's shape is that of an oblate spheroid (it possesses a slight but noticeable bulge around the equator). Jupiter is one of the four gas giants; that is, it is not primarily composed of solid matter. It is the largest planet in the Solar System. Jupiter is thought to consist of a dense core with a mixture of elements, a surrounding layer of liquid metallic hydrogen with some helium, and an outer layer predominantly of molecular hydrogen. 


Saturn 



      
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn, along with Jupiter, Uranus and Neptune, is classified as a gas giant. Saturn has an average radius about nine-times larger than Earth's. Because of Saturn's large mass and resulting gravitation, the conditions produced on Saturn are extreme. Saturn has nine rings, consisting mostly of ice particles with a smaller amount of rockydebris and dust. Saturn's atmosphere exhibits a banded pattern similar to Jupiter's (the nomenclature is the same), but Saturn's bands are much fainter and are also much wider near the equator. Saturn's usually bland atmosphere occasionally exhibits long-lived ovals and other features common on Jupiter. Saturn has an intrinsic magnetic field that has a simple, symmetric shape—a magnetic dipole.


Uranus 


       
Uranus is the seventh planet from the Sun, and the third-largest and fourth most massive planet in the Solar System. Uranus is similar in composition to Neptune, and both are of different chemical composition than the larger gas giants Jupiter and Saturn. Uranus had been observed on many occasions before its discovery as a planet, but it was generally mistaken for a star. The total mass of ice in Uranus's interior is not precisely known, as different figures emerge depending on the model chosen. The bulk compositions of Uranus and Neptune are very different from those of Jupiter and Saturn, with ice dominating over gases, hence justifying their separate classification as ice giants.Uranus's internal heat appears markedly lower than that of the other giant planets; in astronomical terms, it has a low thermal flux.


Neptune


   
Neptune is the eighth and farthest planet from the Sun in our Solar System. Neptune is similar in composition to Uranus, and both have compositions which differ from those of the larger gas giants Jupiter and Saturn.  Neptune's atmosphere, while similar to Jupiter's and Saturn's in that it is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, contains a higher proportion of "ices" such as water, ammonia and methane. Neptune's internal structure resembles that of Uranus. Neptune also resembles Uranus in its magnetosphere, with a magnetic field strongly tilted relative to its rotational axis. Neptune's bow shock, where the magnetosphere begins to slow the solar wind, occurs at a distance. Neptune has a planetary ring system, though one much less substantial than that of Saturn. Neptune's more varied weather when compared to Uranus is believed to be due in part to its higher internal heat.