Title: (Example Article) ⊚ Solar System
Date: 2016-11-12 09:00
Category: Space Science
Tags: planets, rings, universe
Slug: solar-system

The **Solar System** is the [gravitationally](https://en.wikipedia.org/wiki/Gravity "Gravity") bound system comprising the [Sun](https://en.wikipedia.org/wiki/Sun "Sun") and the objects that orbit it, either directly or indirectly. Of those objects that orbit the Sun directly, the largest eight are the [planets](https://en.wikipedia.org/wiki/Planet "Planet"), with the remainder being significantly smaller objects, such as [dwarf planets](https://en.wikipedia.org/wiki/Dwarf_planet "Dwarf planet") and [small Solar System bodies](https://en.wikipedia.org/wiki/Small_Solar_System_body "Small Solar System body"). Of the objects that orbit the Sun indirectly, the [moons](https://en.wikipedia.org/wiki/Natural_satellite "Natural satellite"), two are larger than the smallest planet, [Mercury](https://en.wikipedia.org/wiki/Mercury_(planet) "Mercury (planet)").

![Solar System]({filename}/images/solar-system.jpg "Solar System")

The Solar System [formed 4.6 billion years ago](https://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System "Formation and evolution of the Solar System") from the [gravitational collapse](https://en.wikipedia.org/wiki/Gravitational_collapse "Gravitational collapse") of a giant interstellar [molecular cloud](https://en.wikipedia.org/wiki/Molecular_cloud "Molecular cloud"). The vast majority of the system's [mass](https://en.wikipedia.org/wiki/Mass "Mass") is in the Sun, with most of the remaining mass contained in [Jupiter](https://en.wikipedia.org/wiki/Jupiter "Jupiter"). The four smaller inner planets, [Mercury](https://en.wikipedia.org/wiki/Mercury_(planet) "Mercury (planet)"), [Venus](https://en.wikipedia.org/wiki/Venus "Venus"), [Earth](https://en.wikipedia.org/wiki/Earth "Earth") and [Mars](https://en.wikipedia.org/wiki/Mars "Mars"), are [terrestrial planets](https://en.wikipedia.org/wiki/Terrestrial_planet "Terrestrial planet"), being primarily composed of rock and metal. The four outer planets are [giant planets](https://en.wikipedia.org/wiki/Giant_planet "Giant planet"), being substantially more massive than the terrestrials. The two largest, Jupiter and [Saturn](https://en.wikipedia.org/wiki/Saturn "Saturn"), are [gas giants](https://en.wikipedia.org/wiki/Gas_giant "Gas giant"), being composed mainly of [hydrogen](https://en.wikipedia.org/wiki/Hydrogen "Hydrogen") and [helium](https://en.wikipedia.org/wiki/Helium "Helium"); the two outermost planets, [Uranus](https://en.wikipedia.org/wiki/Uranus "Uranus") and [Neptune](https://en.wikipedia.org/wiki/Neptune "Neptune"), are [ice giants](https://en.wikipedia.org/wiki/Ice_giant "Ice giant"), being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called [volatiles](https://en.wikipedia.org/wiki/Volatiles "Volatiles"), such as water, [ammonia](https://en.wikipedia.org/wiki/Ammonia "Ammonia") and [methane](https://en.wikipedia.org/wiki/Methane "Methane"). All planets have almost circular orbits that lie within a nearly flat disc called the [ecliptic](https://en.wikipedia.org/wiki/Ecliptic "Ecliptic").

    Source: [https://en.wikipedia.org/wiki/Solar_System](https://en.wikipedia.org/wiki/Solar_System)