2. STARS AND GALAXIES
The Sun
1. Sun is necessary for us, made up of hot gasses
(hydrogen), 150 million km, 100x wider than the Earth.
Temperature 5500°C - 6000°C.
2. The structure of the Sun. See above diagrams

3. Photosphere
•Consider the surface of Sun
•Light ball (luminous surface) visible from the Earth
•All the light energy received , comes from the
photosphere.
Core
•Center of The Sun
•Temperature 15000000 °C
•Hidrogen change into helium and release huge
amount of energy

4. Corona
•Only can be seen during Eclipse
•Appears as ring of whitish blue light
Chromosphere
•Layer made up of Hydrogen, Helium and Calcium
•Only can be seen during Eclipse
•Appears as ring of purplish red light

6. STARS AND GALAXIES
The phenomena on the surface of the Sun
sunspot
prominences
Solar flare

7. Solar flare on 31st august 2012

8. The effect of solar flares and prominences on the earth
1. Release solar material (consists of hot electrical charged &
magnetised particles) into space travelling at supersonic speed
2. The continuous flow of these particles called solar wind that flows
past the earth & affect people. See pg 181

9. The effect of solar flares and prominences on the earth
3. The other effect is aurorae. The solar wind collide with oxygen &
nitrogen, causing them release energy in the form of light. North &
south poles

10. aurorae

11. How energy generated by the sun
1. Through nuclear fusion (nuclear reaction) in the core
producing large amount of energy.
2. Under high temperature, hydrogen undergo nuclear
fusion to form helium produces energy in the form of
light and heat
3. Hydrogen atoms nuclear fusion helium atoms + energy

12. Various types of stars (pg 184)

13. Born and death of a star

14. The galaxies
elliptical
irregular
spiral