Earth formed over 4.5 billion years ago from a swirling ... Keep reading to learn more about Earth's different layers, its atmosphere, and what makes the "blue planet" unique.

The Earth's interior is composed of four layers, three solid and one liquid—not magma but molten metal, nearly as hot as the surface of the sun. The deepest layer is a solid iron ball, about ...

The Earth has a layered structure made up of the core, the mantle and the crust. Different elements are present in different parts of the Earth’s structure. The crust is made from enormous ...

It is widely believed that Earth's atmosphere has been rich in oxygen for about 2.5 billion years due to a relatively rapid ...

Earth does have a sodium layer in the upper atmosphere. "For me ... A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). WASP-121b is tidally locked ...