1. Electromagnetic Spectrum
Chapter 28.1
Electromagnetic Spectrum

2. Electromagnetic Spectrum
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
Electromagnetic Spectrum

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

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. Emission Spectrum of Hydrogen
Absorption Spectrum of Hydrogen
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.

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

29. Ed talk: http://ed.ted.com/lessons/what-light-can-teach-us-about-the-universe-pete-edwards
Big Bang Theory:

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

31. Dark Line Spectrum

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

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

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

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

46. X-Ray Black Holes

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

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

49. Astronomer view Space through different types of Telescopes

50. Optical Telescopes
Telescopes gather far more light than the unaided eye can gather.
Telescopes magnify images.

51. 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)

53. Reflecting Telescope
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.

55. Reflector Scopes

56. Galaxy viewed through Optical wavelengths

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

58. Lovell Radio Telescope

59. Cambridge Radio Telescope

62. Aricebo Radio Telescope

65. Galaxy viewed through Radio wavelengths

66. Other Types of Telescopes

67. COBE (Cosmic Background Explorer)

68. Cosmic Background Radiation From Big Bang

69. Milky Way Galactic Center

73. Compton Gamma Ray Telescope

74. ASCA

75. ASCA X-Ray Pulsar

76. ASCA X-Ray Black Hole

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

85. IRAS Infrared Observatory

86. IR Man!

87. Infrared Milky Way Galactic Plain