Our Star the Sun Our Star….. the Sun

The Layers of the Sun

Corona – forms the Sun’s outer atmosphere and can extend far into space. It can only be seen during an eclipse. Chromosphere – the region below the corona deep red in color that can only be seen during an eclipse.

The Sun’s Corona

The Chromosphere

Photosphere – this is the part of the sun seen from Earth where the gases are thick. Also considered the Sun’s surface.

The Photosphere

Convective zone – A part of the sun about 200,000 km thick where the gases circulate in convection currents. Radiative zone – A very dense region of the sun about 300,000 km thick where it takes light millions of years to pass through. Core - the center of the sun where fusion takes place. Temperatures reach 15,000,000 C.

Internal Structure of the Sun

Nuclear Fusion The process by which two or more atoms are joined together or fused to form a larger more massive element. In the case of the Sun…. Hydrogen (H) atoms are fused together to form helium (He). During this process a lot of energy is produced and released.

Hydrogen Fusion

The Sun shines because it is hot. The Sun is hot because in its core, nuclear fusion is producing energy The nuclear fusion that is happening in the Sun's core is the fusion of hydrogen into helium. From models of stars and the Sun, we estimate that this fusion process will keep the Sun shining as it does today for another 4-5 billion years.

Sunspots