Sci. 2-2 The Sun: Our Very Own Star Pages 43-47

A. The sun is a gaseous sphere made primarily of hydrogen and helium.

B. Layers of the Sun

1) core- where the sun’s energy is produced

2) Radiative zone- densely packed atoms 300,000 km thick

3) Convective Zone- convection current of gases – hot goes up, cooler gases sink

4) Photosphere- gases are thick enough – it’s the visible surface

5) Chromosphere- hard to see, below corona

6) Corona- sun’s outer atmosphere- can only be see during a total eclipse

C. The sun produces energy in its core by a process called nuclear fusion.

1) Nuclear Fusion- when two or more nuclei with small masses join together or fuse, to form a larger more massive nucleus. Lots of energy is produced during this process.

2) Matter can be converted to energy- Einstein – Energy = mass times ( speed of light) squared

3) Temperature and pressure are so high, hydrogen nuclei have enough energy to combine and change into helium.

D. Sunspots are darker, cooler areas of the sun caused by changes in the sun’s magnetic fields.

E. Solar Flares are giant storms on the sun’s surface.

F. Auroras are spectacular light shows caused by the interaction of solar particles with the Earth’s upper atmosphere.