Earth is the third planet from the sun and the only known planet in the universe that supports life. It has a diameter of approximately 12,742 kilometers and is the fifth largest planet in the solar system. Earth has a rocky surface and is composed of various elements such as iron, oxygen, silicon, and magnesium.
The Earth’s atmosphere is primarily composed of nitrogen (78%) and oxygen (21%) with small amounts of other gases such as carbon dioxide, neon, and helium.