Sun

The Sun (also known as Cadceed) is the star at the center of the solar system. It is a large sphere of hot gas, composed primarily of hydrogen and helium. Its gravity holds in orbit the planets, asteroids, and comets that revolve around it.

The Sun's energy comes from nuclear fusion occurring in its core, where hydrogen atoms fuse together to form helium. This energy reaches Earth as light and heat, and is the foundation of life, climate, and the water cycle.

Structure

The Sun is divided into layers. The core is where fusion takes place. Below the surface are the radiative zone and the convective zone. The visible surface is called the photosphere, from which light escapes. Above it lie the chromosphere and corona, the outermost and extremely hot layers.

Activity

The Sun has a variable magnetic field. Dark patches called sunspots appear on its surface, and their number follows a cycle spanning several years. Solar flares and waves of energy also erupt from the corona; these can affect radio communications and electrical grids on Earth.

Relationship with Earth

Earth orbits the Sun once per year. The tilt of Earth's axis produces the seasons. Sunlight reaches Earth in a matter of minutes. The solar wind interacts with Earth's magnetic field, creating auroras in the sky.