Γη, or Earth, is the third planet from the Sun in our solar system. It is the only known planet to support life, with a diverse range of ecosystems, climates, and geographical features. The planet has a diameter of about 12,742 kilometers and is primarily composed of rock and metal. The surface of Γη is covered by approximately 71% water, mainly in the form of oceans. The atmosphere is rich in nitrogen and oxygen, which are essential for life. Key processes such as the water cycle and plate tectonics shape the planet's environment and influence weather patterns and geological activity.