Erde

Erde, or Earth in English, is the third planet from the Sun and the only known celestial body to harbor life. It is the largest of the terrestrial planets by mass and volume, with a diameter of about 12,742 kilometers and a mass of roughly 5.97 × 10^24 kilograms. Its surface is about 71 percent water and 29 percent land.

Earth orbits the Sun at about one astronomical unit on a slightly elliptical path, completing a year in roughly 365.25 days. It spins on its axis about every 23 hours 56 minutes (a sidereal day), yielding a mean solar day of 24 hours. The axial tilt of about 23.4 degrees drives the seasonal cycle and climatic variation.

The planet’s internal structure comprises a crust, a mantle, and a core. The outer core is liquid iron-nickel, while the inner core is solid. The circulating liquid in the outer core generates a magnetic field that shields the surface from charged solar particles. The crust includes continental and oceanic types, moving slowly through plate tectonics.

Earth’s atmosphere is a thin envelope of gases dominated by nitrogen (about 78%) and oxygen (about 21%), with traces of argon, carbon dioxide, and neon. Combined with abundant liquid water and biologically produced gases, this environment supports a diverse biosphere. The oceans act as a major component of the climate system and carbon cycle.

The Moon is Earth's natural satellite, about 384,000 kilometers away, completing an orbital period of 27.3 days (sidereal) or 29.5 days (synodic). Tidal interactions influence oceans and rotation. In German, Erde also denotes soil or ground; the article focuses on the planet.