• Earth

    Earth is the planet that humans call home and is the fifth largest planet in the solar system.  It is the third from the sun and the only planet that was not named after Roman or Greek mythology. Earth was not considered to be a planet until the sixteenth century due to the fact that it was not observed from an objective standpoint.

    The earth has a fairly complicated atmospheric composition when compared to the other planets and involves several levels. Most of the mass that makes up the Earth is mantle with the rest considered to be the core.

    The core of the Earth is mostly made of iron although there are a few lighter elements such as nickel in there as well.  At the core temperatures can reach as high as 7500K even though temperatures on the surface never reach that high naturally apart from volcanoes.

    One significant difference between the other eight planets and the Earth is that the Earth’s crust is separated into tectonic plates that move and shift.  Presently eight plates make up the entire crust of the Earth.  Earth is also the only planet where oxygen is rapidly produced and where water exists in a liquid form.