1. Stars, Galaxies, and the Universe- Course 3
3-6 The Sun

2. Vocabulary
Core- The central region of the sun, where nuclear fusion takes place Nuclear Fusion- The process in which two atomic nuclei combine to form a larger nucleus, forming a heavier element and releasing huge amounts of energy; the process by which energy is produced in stars. Radiation Zone- A region of very tightly packed gas in the sun’s interior where energy is transferred mainly in the form of electromagnetic waves. Convection Zone- The outermost layer of the sun’s interior Photosphere- The inner layer of the sun’s atmosphere that gives off its visible light; the sun’s surface.

3. Vocabulary
Chromosphere- The middle layer of the sun’s atmosphere Corona-The outer layer of the sun which looks like a white halo around the sun; Corona means “crown” in Latin Solar Wind- A stream of electrically charged particles that emanate from the sun’s corona Sunspot- 1. A dark area of gas on the sun’s surface that is cooler that surrounding gases 2. Relatively dark, cool region on the surface of the sun Prominence- A huge, reddish loop of gas that protrudes from the sun’s surface, linking parts of sunspot regions Solar Flare- An eruption of gas from the sun’s surface that occurs when the loops in sunspot regions suddenly reconnect

4. My Planet Diary pg. 122 Left in the Dark
On March 13, 1989, a flood of electric particles from the sun reached Earth, causing a magnetic storm. Bright streamers of color filled the sky as far south as Jamaica. But in Quebec, Canada, the storm brought problems. At 2:45 A.M., the entire electric power system collapsed. People woke up with no heat or light. Traffic snarled as traffic lights and subways stopped working.
How could particles from the sun take out a power system? The magnetic storm caused an electrical surge through the power lines. Electric stations couldn’t handle the extra electricity, and they blew out, taking the power system with them.

5. What is the Structure of the Sun? pg. 123
The sun has no solid surface. About three-fourths of its mass is hydrogen, and about one-fourth is helium. The sun has an interior and an atmosphere. The interior includes the core, the radiation zone, and the convection zone.

6. Layers of the Sun pg. 123
THE CORE- The sun produces a large amount of energy in its core though nuclear fusion, a process in which hydrogen atoms join together to form helium. THE RADIATION ZONE – The energy produced in the sun’s core moves outward through the radiation zone mainly in the form of electromagnetic radiation. THE CONVECTION ZONE - The outermost layer of the sun’s interior is called the convection zone. In this zone, energy moves toward the sun’s surface by convection.

7. Layers of the Sun
Core- Center of the sun where nuclear fusion occurs and creates the sun’s energy
Radiation Zone- A region of tightly packed gas where energy moves as electromagnetic radiation. The Zone is so dense that energy takes >100,000 years to move through it.
Convection Zone- The outer most layer. Hot gases rise from the bottom of the convection zone and cool as they reach the top. Cooler gases sink , forming loops of gas that move energy toward the sun’s surface.

8. The Sun’s Atmosphere pg. 124
Like the sun’s interior, its atmosphere is composed mainly of hydrogen and helium. The sun’s atmosphere includes the photosphere, the chromosphere, and the corona. Each layer has unique properties.
The photosphere is the inner layer.
The chromosphere is the middle layer.
The corona is the outer layer.
The corona extends far into space. It gradually thins into streams of electrically charged particles called the solar wind.

9. Solar Temperature pg. 125
Which layer is the hottest?_______________________________
How does the temperature change in the sun’s atmosphere differ from the temperature change in the sun’s interior?
_________________________________________________________

10. Assess Your Understanding pg. 125
1a. List- List the layers of the sun’s interior and atmosphere, starting from the center. ________________________________ ______________________________________________________________________________________________________ b. Compare and Contrast- What is one key difference between radiation and convection zones? _________________________ I get it! Now I know that the sun’s structure incluudes _________

11. What Features Can You See On the Sun? pg. 126
Features on or just above the sun’s surface include sunspots, prominences, and solar flares.
Sunspots are areas of gas on the sun’s surface that are cooler than the gases around them. Sunspots usually occur in groups.
Huge loops of gas called prominences link different parts of sunspot regions.
When loops in sunspot regions suddenly connect, they release large amounts of magnetic energy. This energy heats the surrounding gas, causing it to erupt into space. These eruptions are called solar flares.

12. Solar Wind pg. 127
Solar wind is made of electrical particles from the sun. Earth’s atmosphere and magnetic field normally block the solar wind. But near the North and South poles, the particles can enter Earth’s atmosphere, where they cause auroras and magnetic storms.

13. Assess Your Understanding pg. 127
2a. Define- (Prominences/sunspots) are loops of gas that extend from the sun’s surface. b. Explain- Why do sunspots look darker than the rest of the sun’s photosphere? ___________________________________________ _______________________________________________________ c. Relate Cause and Effect- How is the solar wind related to magnetic storms on Earth? _________________________________ I get it! Now I know that features on the sun include______________