1. THE SUN NOTES

2. LAYERS of the Interior THE CORE- Nuclear Fusion occurs Diameter- 400,000 km The Radiation Zone- region of compressed gas and energy is transferred by electromagnetic waves. Thickness- 300,000 km Very Dense zone- can take energy 100,000 years to pass through The Convection Zone- energy is transferred outward through convection currents Thickness- 200,000 km

3. Layers of the Atmosphere Photosphere- Visible surface of the sun (photo=light) that is not solid but considered the surface 500 km thick and 5800 degrees Kelvin Chromosphere- Middle layer of the atmosphere that emits a reddish light (chromosphere means sphere of color) 10,000 degrees Kelvin Visible only during a total solar eclipse Corona- outermost layer means the crown 1million degrees Kelvin Low density- extends millions of miles into space Where solar winds come from and produces the auroras when they enter the earth’s atmosphere.

4. Features on the Sun Sun Spots- areas of gas that are cooler than the surrounding gas Can be larger than the size of Earth and can last hours to a few months Prominences- huge loops of gas that erupt from the sun spot regions Can reach heights of more than 100,000 km above the sun’s surface Solar Flares- Sun’s surface erupts producing X-rays and charged particles Occur near sunspots Heat the corona up to 20 million Kelvin When the particles reach Earth they can cause magnetic storms which disrupt power, radio, TV, cell phone reception

5. The Layers and Features of the Sun

6. The Sun’s Energy Most Energy is in the form of electromagnetic radiation The sun is approx. 4.6 Billion years old Energy is produced in its core by the fusion of hydrogen Hydrogen nuclei collide to form helium This releases large amount of energy Forces in the Sun- inward and outward forces must be equal Thermal Pressure pushing out = Gravity pulling in The sun remains stable as long as there is a steady energy source = estimated time… 5 billion years

7. Incoming Solar Radiation on Earth Of 100% of the incoming solar radiation about 51% is absorbed by the earth and the rest either is 1.19 %Absorbed by the atmosphere 2.30% Reflected or scattered back into space by earth or clouds

8. Scattering Why is the sky blue? Why are our sunsets red? Molecules of dust and gas will interfere with the incoming solar radiation. It will scatter the shorter wavelengths of visible light which happen to be the color blue. When the sun is in a lower angle in the sky like during sunrise and sunset, the rays have to travel longer and through a thicker atmosphere. The blue is scattered to a large extent and we see what is left in the spectrum which is the orange/red colors.