1. Our Star the Sun
Our Star….. the Sun

2. The Layers of the Sun

3. 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.

4. The Sun’s Corona

5. The Chromosphere

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

7. The Photosphere

8. 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.

9. Internal Structure of the Sun

10. 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.

11. Hydrogen Fusion

12. 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.

13. Sunspots