1. Notes 16- 2 The Sun

2. Stars an object that produces it own energy, including heat and light.

3. The Sun is a Star Star made of hydrogen and helium located at the center of the solar system and is also the largest object Has a strong gravitational pull which holds planets in orbit 4.6 billion years old

4. The size of the Sun If the Sun were a hollow ball more then a million Earths could fit inside it! The Sun is an average size star and the largest object in the solar system. The Sun looks larger than the other stars that can be seen in the night sky because it is much closer to Earth.

5. The sun is gas! The Sun is a huge sphere made up of mostly of two gases. –71% of the Sun’s mass is Hydrogen –27% of the Sun’s mass is Helium –The remaining 2% is Oxygen and Carbon

6. What happens inside the Sun? Hydrogen particles smash together to make helium. This smashing is called Nuclear Fusion. A little bit of mass is a lost when hydrogen particles combine to make helium. The mass in turned into energy We see this energy as light and heat!

7. Interior Layers: The sun has 3 interior layers: 1) the core 2) the radiation zone 3) the convection zone

9. The Core Most of the energy that the Sun produces is formed in it’s core. The Core’s temperature is 10 million to 20 million degrees Celsius. The pressure is more than 1 billion times greater then the air pressure of Earth.

10. Radiation Zone Next to the core Moves the energy produced in the core in every direction. It can take >100,000 years for energy to move out of this layer.

11. Convection Zone Layer next to the radiation layer Gasses with different energies move in circles in a way similar to air with different densities. Energy moves out of this layer in about a week.

12. The sun’s atmosphere: Has 3 layers: 1) photosphere 2) chromosphere 3) corona

13. Photosphere Is the visible surface of the Sun. It is not a solid surface, but rather a layer of thick gasses. Gives off visible light

14. Chromosphere Is the inner layer of the Sun’s atmosphere. When it can be seen it looks like a red circle around the Sun.

15. The Corona The outermost layer of the Sun’s atmosphere which creates solar winds. The corona takes on different shapes around the Sun depending on changes in the temperature of the photosphere.

16. Solar Flares Are bursts (eruptions) of heat and energy that stretch out from the corona and chromospheres into space. Sometimes the energy disrupts satellites, interfering with TV, radio, and cell phone communication systems.

17. Aurora Borealis Also called the Northern Lights Energy from the solar flares increases solar winds, causing displays of different- colored lights in the upper atmosphere. Most often seen in Alaska, Canada, and the Northern United States

20. Sun Spots Solar Flares are also sometimes associated with sunspots They are dark spots on the Sun. They are regions of the photosphere that have a lower temperature then the surrounding regions therefore they give off less light.