Solar system

A genericogólny solar systemukład słoneczny (or planetary system) consists of at least one star and various orbitingto orbit: krążyć wokół objects (such as asteroids, comets, moons, and planets). The term originated to describe the planetary system around Sol, the Latin name for our sun. The planet Earth is located within our solar systemukład słoneczny, which is usually called simply the Solar system; others are called planetary systems to avoid confusionzamieszanie. This article uses this terminology.


Solar system objects

The wide variety of objects that exist in the solar systemukład słoneczny fall into several
categories. In recent years many of these categories have been found to be less
clear-cutwyraźny than once thought. This encyclopedia employs the following divisionspodziały:

• The Sun is a spectralwidmowy, spektralny class G2 star that contains 99.86% of the system's
  mass.


• The planets of the solar systemukład słoneczny are those nine bodies traditionally labelledto label: oznaczać
  as such: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and
  Pluto.
  
  
  
  • Sizeable objects that orbit these planets are moons. For
    a complete listing, see that article.
  
  
  • Dust and other small particlesdrobinki, cząstkicząstki that orbit these planets
    form planetary rings.
  
  
  • Space debrisgruz of artificialsztuczne originpochodzenie that can be found in
    orbit around Earth.
  
  
  • Planetesimals, from which the planets were originally
    formed, are sub-planetary bodies that accretedto accrete: narastać, gromadzić się during the first years
    of the solar systemukład słoneczny and that no longer exist. The name is also sometimes
    used to refer to asteroids and comets in general, or to asteroids belowponiżej
    10km in diameterśrednica.
  
  
  
  


• Asteroids are objects smaller than planets that lie roughlyw przybliżeniu
  within the orbit of Jupiter and are composed in significant part of nonvolatile
  minerals. They are subdividedto subdivide: dzielić na mniejsze częścito subdivide: dzielić się dalej into asteroid groups and asteroid families based
  on their specific orbital characteristicswłaściwości.
  
  
  
  • Asteroid moons are asteroids that orbit larger asteroids.
    They are not as clearly distinguishedto distinguish: odróżniać as planetary moons, sometimes being
    almost as large as their partners.
  
  
  • Trojan asteroids are located in either of Jupiter's L₄
    or L₅ points, though the term is also sometimes used for asteroids
    in any other planetary Lagrange point as well.
  
  
  • Meteoroids are asteroids that range in size from roughlyw przybliżeniu
    bouldergłaz sized to particlesdrobinki, cząstkicząstki as small as dust.
  
  
  
  


• Comets are composed largely of volatileniestabilne, lotne ices and have highly
  eccentricwydłużony orbits, generally having a periapsis within the orbit of the innerwewnętrzny
  planets and an apoapsis beyond Pluto. Short-period comets exist with apoapses
  closer than this, however, and old comets that have had most of their volatiles
  driven out by solar warming are often categorizedto categorize: klasyfikować as asteroids. Some comets
  with hyperbolic orbits may also originatepowstaćzapoczątkować outside the solar systemukład słoneczny.


• Centaurs are icylodowe comet-like bodies that have less-eccentricwydłużony
  orbits so that they remainpozostawać in the region between Jupiter and Neptune.


• Trans-Neptunian objects, which are icylodowe bodies whose mean orbital
  radiuspromień lies beyond Neptune's. These are further subdividedto subdivide: dzielić na mniejsze częścito subdivide: dzielić się dalej:
  
  
  
  • Kuiper beltpas, strefa objects have orbits lying between 30 and 50
    AU. This is thought to be the originpochodzenie for short-period comets. Pluto is
    sometimes classified as a Kuiper beltpas, strefa object in addition to being a planet,
    and a class of Kuiper beltpas, strefa objects with Pluto-like orbits are called Plutinos.
    The remainingpozostający Kuiper beltpas, strefa objects are classified as Cubewanos in the main
    beltpas, strefa and scatteredrozrzucony, rozproszony disk objects in the outerzewnętrzny fringeskrawędzie.
  
  
  • Oort cloud objects, currently hypotheticalhipotetyczny, have orbits
    lying between 50,000 and 100,000 AU. This region is thought to be the
    originpochodzenie of long-period comets.
  
  
  • The newly discovered object Sedna, with a highly elliptical
    orbit extendingto extend: rozciągać się from about 76 to 850 AU, does not obviouslyoczywiście fitpasować in either
    category, although its discoverersodkrywcy arguespierać sie that it should be consideredto consider: uważać za
    a part of the Oort cloud.
  
  
  
  


• Small quantitiesilości of dust are present throughoutprzez cały the solar
  system and are responsible for the phenomenon of zodiacal light. Some of the
  dust is likely interstellarmiędzygwiezdny dust from outside the solar systemukład słoneczny.

Origin and evolution of planetary systems


Planetary systems are generally believed to form as part of the same process which results in star formation; although, some arguespierać sie that systems are formed by some kind of accidental "stellargwiezdny near-collison". The more common theory argues that the objects of a planetary system developedto develop: rozwijać się from a solar nebulamgławica.



Orbit of the solar systemukład słoneczny



The solar systemukład słoneczny is part of the Milky Way galaxygalaktyka, a spiral galaxygalaktyka with a diameterśrednica of about 100,000 light years containing approximately 200 billion stars, of which our Sun is fairlydośc, dosyć typical.

Estimates place the solar systemukład słoneczny at between 25,000 and 28,000 light years from the galactic center. Its speed is about 220 kilometers per second, and it completes one revolutionobieg every 226 million years.

The solar systemukład słoneczny appears to have a very unusual orbit. It is both extremely close to being circular, and at nearly the exact distance at which the orbital speed matches the speed of the compressionściskanie waves that form the spiral arms. The solar systemukład słoneczny appears to have remained between spiral arms for most of the existence of life on Earth. The radiationpromieniowanie from supernovae in spiral arms could theoretically sterilize planetary surfacespowierzchnie, preventing the formation of large animal life on land. By remainingpozostający out of the spiral arms, Earth may be unusually free to form large animal life on its surfacepowierzchnia.




Discovery and exploration of the solar systemukład słoneczny



Because of the geocentric perspective from which humans viewed the solar systemukład słoneczny, its nature and structure were long misperceivedto misperceive: błędnie postrzegać. The apparentpozorne motionsruchy of solar systemukład słoneczny objects as viewed from a moving Earth were believed to be their actualrzeczywiste motionsruchy about a stationarynieruchomy Earth. In addition, many solar systemukład słoneczny objects and phenomena are not directly sensiblepostrzegalny by humans without technical aidspomoce. Thus both conceptualpojęciowe and technological advancespostępy were required in order for the solar systemukład słoneczny to be correctly understood.

The first and most fundamentalpodstawowe of these advancespostępy was the Copernican Revolution, which adopted a heliocentric model for the motionsruchy of the planets. Indeed, the term "solar systemukład słoneczny" itself derives from this perspective. But the most important consequences of this new perceptionpostrzeganie came not from the central position of the Sun, but from the orbital position of the Earth, which suggested that the Earth was itself a planet, and the planets other Earths. This was the first indicationoznaka of the true nature of the planets. Also, the lack of perceptibledostrzegalny stellargwiezdny parallax despitepomimo the Earth's orbital motion indicated the extreme remotenessoddalenie of the fixednieruchomy stars, which promptedto prompt: wywoływać the speculation that they could be objects similar to the Sun, perhaps with planets of their own.




The solar systemukład słoneczny and other planetary systems



Until recently, the solar systemukład słoneczny was the only known example of a planetary system, although it was widely believed that other comparableporównywalne systems did exist. A number of such systems have now been detectedto detect: wykrywać, although the information availabledostępny about them is very limited. The technique employed involves the detection through the Doppler effect of periodic variationsodmiany in the motion of parent stars which is attributedto attribute: przypisywać to the presence of planets. This allows the mass and orbital characteristicswłaściwości of the unseenwcześniej nie widziany planets to be determined. Unfortunately the sensitivitywrażliwość of these techniques currently does not permitto permit: pozwalać na the detection of planets of mass and orbit comparableporównywalne to the Earth.

Url źródłowy: http://en.wikipedia.org/wiki/Solar_system

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