1. Outline of Space Unit Earth’s Moon (ch. 25)
The Sun and the Solar System (ch. 26)
The Planets and the Solar System (ch. 27)
Stars and Galaxies (ch. 28)

2. Stars and Galaxies (ch. 28) Learning Objectives
Light
Describe electromagnetic radiation
Explain how light is used to learn about stars
Explain how the Doppler effect is used to learn about star motion
Stars
Explain why constellations appear to change position each season
List units astronomers use to measure distances to stars
Describe the different characteristics of star

3. Stars and Galaxies (ch. 28) Learning Objectives
3. Life of a star
A. Main sequence
B. Exceptions
C. HR diagrams
D. The cycle
4. Define galaxy and describe the various types
5. Explain the origin of the universe according to the big bang model
and horseheadnebula.jpg

4. 1. Light
CPS 1-2
Electromagnetic radiation is energy released by stars in the form of waves (see ESRT)
Many types, together known as electromagnetic spectrum (visible light is only 1 kind)
Types have different wavelengths

5. 1. Light

6. 1. Light cont’d
CPS 3-5
3. Wavelength varies indirectly with energy content
Which is more energetic red or violet?
Observe an exploded star at different wavelengths. Vis.

7. Stars and Galaxies (ch. 28) Learning Objectives
Light
Describe electromagnetic radiation
Explain how light is used to learn about stars
Explain how the Doppler effect is used to learn about star motion
Stars
Explain why constellations appear to change position each season
List units astronomers use to measure distances to stars
Describe the different characteristics of star

8. 1. Light cont’d
B. Astronomers use a spectroscope to study types of star spectra (sing. spectrum)
1. Continuous spectrum- source emits light of all wavelengths
2. Emission spectrum- source emits some wavelengths
3. Absorption spectrum- cool gases absorb some wavelengths depending on their composition

9. 1. Light cont’d Looking at Starlight exercise
Emission spectra act as fingerprints, allowing astronomers to identify the ingredients of stars
Looking at Starlight exercise

10. Stars and Galaxies (ch. 28) Learning Objectives
Light
Describe electromagnetic radiation
Explain how light is used to learn about stars
Explain how the Doppler effect is used to learn about star motion
Stars
Explain why constellations appear to change position each season
List units astronomers use to measure distances to stars
Describe the different characteristics of star

11. 1. Light cont’d
C. Doppler effect- used to determine movement based upon wavelength

12. 1. Light cont’d
C. Doppler effect- used to determine movement based upon wavelength
1. Objects approaching seem to have a shorter wavelength
2. Objects receding seem to have a longer wavelength
Hear Doppler effect of a car horn…CarDoppler.MOV
Observe the change in a star's spectrum as its motion changes.