1. Here Comes the Sun!!
Chapter 14
Section 2
Page 545
Miss Sullivan
Rm B2

2. The Sun The sun is the closest star to Earth
It is approximately 93 million miles or 150 million kilometers away (1 astronomical unit)
It provides almost all of the energy for life on Earth
It also accounts for 99.8% of the total mass of our solar system

3. The Sun’s Energy The sun’s energy is produced through nuclear fusion.
Nuclear fusion is when two smaller atomic nuclei (hydrogen) are fused or joined together to form a more massive nucleus (helium) and releasing energy.
This fusion happens only under intense pressure and temperature

4. Nuclear Fusion
During nuclear fusion, two atomic nuclei collide and fuse.

5. Forces in Balance
Nuclear fusion in the sun’s core produces an incredible amount of energy.
This energy causes gas ions within the sun to move very fast, generating a tremendous pressure pushing outward from the core.
This pressure would cause the sun to explode if it weren’t balanced by an equal and opposite force The balancing force is gravity.
The weight of matter pushing inward and the outward pushing pressure are balanced throughout the sun.

6. The Layers of the Sun
The sun has an interior and an atmosphere, each of which consists of several layers.

7. The Sun’s Interior
Convection Zone --- where hot gases form convection currents
Radiation Zone --- a place of condensed gases that transfer electromagnetic radiation
The Core --- where nuclear fusion takes place

8. The Sun’s Atmosphere The sun’s atmosphere has 3 layers:
The Photosphere
the sphere that “gives off light”
The Chromosphere
a thin layer of color
The Corona
the outer white halo that extends millions of kilometers into space

9. The Sun
Features on or above the sun include sunspots, prominences, and solar flares.

10. Sunspots
Sunspots look like small dark areas on the sun’s surface (some are actually as big as the Earth!)
Sunspots are areas of gas on the sun that are cooler than the gases around them.
Cooler gases don’t give off as much light as the hotter gases.
Sunspots actually occur in cycles and can be linked with weather here on Earth!

11. Sunspots and Weather
Evidence that supports that theory that sunspots cycles influence weather include:
Little Ice Age: most parts of the world experienced cold harsh weather.
Little Ice Age is associated with low sunspot activity between (these are called minimums)
Low sunspot activity occurs every 500 years, perhaps another Little Ice Age will occur in 2050! (41 years from now…how old will you be?)

12. Prominences
Prominences: Reddish loops of ionized gas that link different parts of sunspot regions.

13. Solar Flares
Solar Flares: When prominences suddenly connect, a large amount of energy is released causing huge explosions of hydrogen (Solar Flares)

14. Solar Wind
Solar flares cause an increase in solar wind that extends the corona into space
An increase is solar winds can cause electromagnetic effects on Earth: auroras, disrupt communications, cause electrical problems

15. Homework Read Chapter 14, Section 2
Do the questions at the end of the section, page 550