1. Fusion vs Fission Fission Fusion Division of an atom’s nucleus
Chain reaction
Uses Uranium 235 to generate energy
Create nuclear waste that lasts 100,000+ years
Fusion
Combination of the nucleus of Hydrogen atoms
Found in stars
Produces no nuclear waste
Lots of energy!!!!

2. Fusion

3. Fission

4. 26.1 THE SUN What is the Sun? What causes the Sun to shine?
How long does it take energy from the Sun to get to Earth?
Why is it said that when we see the stars we see history?

5. Sun-General Info Composed of H (70%) & He (28%)
Most atoms are stripped of their electrons
Forms a plasma of ionized gas
Approx. 15 million K at core & 5800 K at surface
(Pressure 340 billion x Earth's pressure

6. Energy from the Sun
Nuclear fusion converts mass into energy in Sun’s core (temp. 27,000,000 F)
Heat & pressure (from gravity) so intense causes nuclei to fuse (Sun’s core)
H (two) nuclei's fused  He = enormous release of heat & energy that blast outward as heat & light (Sun’s core)

7. Force & Balance
Energy from nuclear fusion at sun’s core – ions move faster
Outward push of thermal (heat) pressure
Gravity pulls gas inward at same time
Sun remains stable due to balance in forces

8. Sun’s Interior : Core & Radiation Zone
Fusion energy moves outward from core two ways :radiation/convection
Radiation zone: regions with highly compressed gas, transferred by the absorption & re-radiation of electromagnetic waves
So dense may take energy from core 100,00 years to move to surface of Sun & escape

9. Convection Zone From radiation zone energy moves into convection zone
Outer layer of Sun’s interior
Energy transferred outward by convection currents
Hot gases rise & cooler gases sink become hot again, etc.

10. Sun’s Atmosphere
Three layers
Photosphere
Chromosphere
Corona

11. Photosphere Innermost layer of sun’s atmosphere Visible surface
500 km thick
5800 K
Sun’s surface –not solid
Bubbly – granular appearance

12. Chromosphere Outside the photosphere 10,000K H emits reddish light
Visible mostly during total solar eclipse

13. Corona Outmost layer of Sun’s atmosphere Very thin gases
1,000,000 K though w/ very low density total amt of thermal energy small compared to total Sun
Extends millions of km above chromosphere
Light energy = photons
No mass, 186,000 m/s
Also visible during solar eclipses
6th period stopped here

14. Solar Wind Stream of electrically charged particles
Flow outward from sun through solar system
Hits earth’s magnetic field where particles are deflected
Produce auroras
3rd period got here

15. Auroras (Northern Lights)

16. Atmospheric Features Sunspots
Areas of darker, cooler gases (only a few million degrees K)
Give off less energy
Some larger than Earth
Found in groups w/ intense magnetic fields
Last days to months
11 year cycles
Show motions of Sun’s surface

17. Atmospheric Features pt. 2
Prominences
Huge loops of gas - erupt from sunspots
Extend upward from photosphere into chromosphere/corona (100,000 km above sun surface)
Travel along magnetic field lines that connect sunspots

18. Atmospheric features pt. 3
Solar flares occur when surface of sun erupts producing x-rays & charges particles at speeds of 1000 km/s or more
Occur near sunspots
Heat parts of corona to 20 million K
Increases solar winds
Disturbs communications, radio, cell phone, TV etc.

19. Sun’s Magnetic Field
Produced on the Sun by the flow of electrically charged ions & electrons
Magnetic forces change the direction & motion of moving charged particles like electrons