Earth. Third planet from the Sun in the Solar System Earth's atmosphere consists mostly of nitrogen and oxygen. More solar energy is received by tropical regions than polar regions and is redistributed by atmospheric and ocean circulation. Greenhouse gases also play an important role in regulating the surface temperature. A region's climate is not only determined by latitude, but also by elevation and proximity to moderating oceans, among other factors. Severe weather, such as tropical cyclones, thunderstorms, and heatwaves, occurs in most areas and greatly impacts life. Earth's gravity interacts with other objects in space, especially the Moon, which is Earth's only natural satellite. According to radiometric dating estimation and other evidence, Earth formed over 4.5 billion years ago. Etymology Historically, earth has been written in lowercase. There are a number of adjectives for the planet Earth.
Chronology Formation Artist's impression of the early Solar System's planetary disk Future Heat.
Name and etymology. Composition and structure. Orbit, rotation, and tilt. Habitability. Earth in culture.