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) http://www.rug.nl/museum/tentoonstellingen/archief/ruimte

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

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 http://www.godandscience.org/images/ngc7009.jpg and horseheadnebula.jpg

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 http://www.yourdictionary.com/images/ahd/jpg/A4wavele.jpg

1. Light http://gtn.sonoma.edu/public/resources/presentations/06_03_02/img003.jpg

1. Light cont’d CPS 3-5 3. Wavelength varies indirectly with energy content Which is more energetic red or violet? http://www.spacetoday.org/images/DeepSpace/Telescopes/GreatObservatories/Chandra/ChandraSpectrum.jpg Observe an exploded star at different wavelengths. Vis.

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

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 http://members.tripod.com/mroleary/sitebuildercontent/sitebuilderpictures/mypicture16.jpeg

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 http://www.physics.utoledo.edu/~lsa/_p1750/SPlab.jpg

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

1. Light cont’d C. Doppler effect- used to determine movement based upon wavelength http://www.glenbrook.k12.il.us/gbssci/phys/Class/waves/u10l3d1.gif

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. http://www.physicsclassroom.com/Class/waves/u10l3d3.gif