1. Chapter 28.1 Electromagnetic Spectrum

2. Scientists learn about the Universe by collecting Wave- Energy from the Electromagnetic Spectrum

3. The Electromagnetic- Spectrum is a continuum depicting the full range of Electromagnetic Radiation, with the longest wavelength at one end, and the shortest at the other.

4. Electromagnetic Radiation is energy in the form of a Wave, resulting from the motion of electric charges and the magnetic fields that they produce.

6. Electromagnetic Spectrum Visible Light

7. Increasing Wavelength Increasing Energy

8. Objects in space emit energy in several different Frequencies and Wavelengths.

10. Wavelength

11. The Wavelength of a Wave

12. The wavelength of each color of light is different Red Light Blue Light

13. Frequency

14. The Spectroscope and the Visible Spectrum When light passes through a prism and out again, they are refracted, or bent, forming a band called the Visible Spectrum.

15. Stars emit light that falls within the visible spectrum. Scientists use an instrument called a Spectroscope to separate this starlight into its colors so that it can be studied.

16. Spectroscopes break light into three different types. Continuous Spectrum Emission Spectrum Absorption Spectrum

17. Each element gives a unique spectrum. The position of the lines relative to one another changes from element to element and, as it turns out, from molecule to molecule. In essence, the emission spectrum is a fingerprint of the element/molecule that generates it.

19. By studying these different spectra, and comparing the emission/absorption spectra of stars to those of gaseous elements in a lab, astronomers can determine the types of elements that make up the atmospheres of the stars that emitted the light. Emission Spectrum of Hydrogen Absorption Spectrum of Hydrogen

23. Solar Spectrum

24. The Doppler Effect Scientists use Spectral Analysis to not only determine what gases are present in stars, but also how they are moving relative to the Earth. This is possible because of a phenomenon called the Doppler Effect.

25. Let’s look at some examples of the Doppler Effect that you have all experienced.

26. Person A Person B Fire Engine at Rest Fire Engine moving to the right, and toward Person B Waves stretchedWaves compressed

29. The Doppler Effect also applies to Light. Bright Line Spectrum

30. Dark Line Spectrum

31. Because of Doppler Shift, scientists have determined that our Universe is expanding

34. Scientists have even been able to use Doppler Shift to detect the “wobble” of Stars with orbiting massive planets.

36. Galaxy moving away-Light shifted toward Red. Galaxy moving toward -Light shifted toward Blue.

37. Stars emit energy in wavelengths that include… 1. Visible Light 2. Infrared 3. Ultraviolet 4. X-Rays 5. Gamma Rays.

45. X-Ray Black Holes

46. UV H Alpha Gamma X-Ray The Sun “viewed” through different wavelengths

47. M82 IR M82 Optical M82 Radio M82 X-Ray

48. Astronomer view Space through different types of Telescopes

49. Optical Telescopes 1.Telescopes gather far more light than the unaided eye can gather. 2.Telescopes magnify images.

50. Refracting Telescope Refracting Telescope- Uses two lenses. The Lense, at the front of the tube, gathers light. The Eyepiece magnifies the image collected by the lense. (limited in size by tendency of large lenses to bend)

52. Reflecting Telescope- Uses one large lense to gather and focus light, then reflect the image to a small mirror, then to an eyepiece on the side. Since the lense is supported, reflecting telescopes can be much larger. Reflecting Telescope

54. Reflector Scopes

55. Galaxy viewed through Optical wavelengths

56. Radio Telescopes (technical term for really big satellite dishes) Used to detect energy waves given off at frequencies lower than visible light.

57. Lovell Radio Telescope

58. Cambridge Radio Telescope

61. Aricebo Radio Telescope

64. Galaxy viewed through Radio wavelengths

65. Other Types of Telescopes

66. COBE (Cosmic Background Explorer)

67. Cosmic Background Radiation From Big Bang

68. Milky Way Galactic Center

72. Compton Gamma Ray Telescope

73. ASCA

74. ASCA X-Ray Pulsar

75. ASCA X-Ray Black Hole

81. “Pillars of Creation” Photographed by the Hubble Telescope (shown left)

84. IRAS Infrared Observatory

85. IR Man!

86. Infrared Milky Way Galactic Plain