1. The Sun’s Size, Heat and Temperature After completing this section, students will explain nuclear fusion, and describe the sun and compare it to other stars (Standard PI – 071 and 072

2. Compared to the Earth, the Sun is enormous. The sun has a diameter of 1,400,000 kilometers (more than 3 times the distance between the earth and the Moon) The Sun could hold 1 million Earths If the sun went dark right now, it would take about 7 minutes for us to find out. It takes that long for the light to get to us

3. Despite all of these examples, the Sun is incredibly average It is of average size, average age and average temperature

4. The Sun and all other stars get their energy from fusion Fusion is the combining of the nuclei of lighter elements to form a heavier

5. In the core of the Sun, hydrogen in the form of plasma, combines to form helium. When this happens, heat and light are produced Plasma – fourth state of matter consisting of charged particles (atoms without electrons)

6. The Sun’s Layers

7. The Core The core contains mostly hydrogen and helium in plasma state. Temperatures in the core reach 15,600,600 degrees Celsius

8. The Radiation Zone This layer is made of plasma also, but much cooler than the core (2-8,000,000 degrees Celsius)

9. The Convection Zone Rising and falling currents of plasma carry energy to the Sun’s surface where it is radiated out into space as sunlight

10. The Photosphere This is the visible surface of the sun. The temperature of the photosphere is 6,000 degrees C.

11. The Chromosphere The inner layer of the Sun’s atmosphere, it extends thousands of kilometers above the surface of the sun

12. The Corona This is the thin outer layer of the Sun’s atmosphere. It has a temperature of 1-3,000,000 degrees Celsius

13. Features on the Sun

14. Granules - visible structures in the photosphere of the Sun arising from activity in the Sun's convective zone

15. A solar prominence is a large bright feature located in the solar corona Prominences are caused by the Sun’s magnetic field

16. A sunspot is a region on the photosphere that is marked by a lower temperature than its surroundings and intense magnetic activity

17. A solar wind is a stream of charged particles ( plasma) which are ejected from the upper atmosphere of a star

18. As the solar wind blows past the Earth, some particles interact with the Earth’s magnetic field These displays of color are called auroras