Inner Planets (Terrestrial Planets)
* Mercury: Primarily composed of iron and nickel (a large metallic core) with a thin silicate mantle.
* Venus: Composed of a thick atmosphere of carbon dioxide, a rocky surface similar to Earth's, and a likely iron core.
* Earth: Has a diverse composition with a solid iron-nickel core, a molten outer core, a silicate mantle, and a thin crust. It's unique in having liquid water on its surface.
* Mars: Composed primarily of iron oxide (giving it its red color), with a smaller iron core, a thin atmosphere, and a rocky surface.
Outer Planets (Gas Giants)
* Jupiter: Composed primarily of hydrogen and helium, with trace amounts of methane, ammonia, and water. It's believed to have a small rocky core.
* Saturn: Similar to Jupiter in composition (mostly hydrogen and helium), but with a lower density. It has a prominent ring system.
* Uranus: Composed mostly of hydrogen and helium, but also contains methane, ammonia, and water. It has a tilted axis and a faint ring system.
* Neptune: Similar composition to Uranus, also with methane, ammonia, and water, giving it a deep blue color. It has a powerful wind system and faint ring system.
Key Differences in Composition:
* Inner planets are rocky and dense, with solid surfaces, while outer planets are gas giants, much larger and less dense with no solid surfaces.
* Inner planets are closer to the sun and formed from the inner, hotter region of the solar nebula, where heavier elements could condense.
* Outer planets formed farther out in the cooler regions of the nebula, allowing lighter elements like hydrogen and helium to accumulate.
Interesting Note:
The distinction between "inner" and "outer" planets is a bit blurry when you consider Pluto, which is considered a dwarf planet. It has a rocky composition with a thin atmosphere and is far from the sun.
