1. The Sun The interior of the sun has three layers:
the core, where energy is produced by nuclear fusion
the radiative zone, where energy is transported by radiation
the convection zone, where energy is transported by convection

2. Layers
The Core The center of the sun, where the energy is produced, 27,000,000 ° F, approximately 347,500 km thick

3. Layers
Radiative Zone
Very dense, about 300,000 km thick

4. Layers
Convective Zone
About 200,000 km thick where gases circulate

5. Layers
Photosphere
The visible part (but not solid) we can see from Earth that is about 100 km thick.

6. Layers
Chromosphere
A thin, irregular region just below the corona, only 30,000 km thick

7. Layers
Corona
The sun’s outer layer, anywhere from 10 km to 100,000 km thick

8. The Sun’s Basic Layers

9. Features in the Photosphere
Notes for HCDE Workshop on Sun and Seasons Feb. 4, 2009
Features in the Photosphere
Sunspots
Dark and small (but brighter than Full Moon and big as Earth)
Cool-- temperatures only 6,200 F (Sun’s surface is 10,000 F)
Associated with magnetic fields: one set of spots is positive, other is negative
Lunar and Planetary Institute

10. Notes for HCDE Workshop on Sun and Seasons Feb. 4, 2009
More on Sunspots
Our Sun has an activity cycle of 11 years
Sunspots appear at specific latitudes on Sun
Bands of latitude move towards equator during cycle
Lunar and Planetary Institute

11. Notes for HCDE Workshop on Sun and Seasons Feb. 4, 2009
Solar Events
Flares (Explosions of energy on the surface of the Sun)
Prominences
Coronal Mass Ejections (massive clouds of plasma ejected from the Sun)
Lunar and Planetary Institute

12. Notes for HCDE Workshop on Sun and Seasons Feb. 4, 2009
Solar Wind
Blows charged particles and magnetic fields away from the Sun
Charged particles captured by Earth’s magnetic field
Create Auroras or Northern and Southern Lights
Lunar and Planetary Institute

13. Notes for HCDE Workshop on Sun and Seasons Feb. 4, 2009
Auroras
Electrons from solar wind are captured by the Earth’s magnetic field
Interact with atoms in our atmosphere: oxygen and nitrogen make red and green; nitrogen can also make violet
Northern lights are Aurora Borealis, while southern are Aurora Australis
Lunar and Planetary Institute

14. Notes for HCDE Workshop on Sun and Seasons Feb. 4, 2009
Coronal Mass Ejection
The eruption of a huge bubble of hot gas from the Sun
This series of images of coronal mass ejections taken with LASCO C3 (May 1-31, 1997) at
Lunar and Planetary Institute

15. Notes for HCDE Workshop on Sun and Seasons Feb. 4, 2009
CME’s effects on Earth
Can damage satellites
Very dangerous to astronauts
Power problems
Animation of a CME leaving the Sun, slamming into our magnetosphere.
Lunar and Planetary Institute