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Studying the Universe

Studying the Universe. Telescopes. Telescopes aid astronomers in 2 ways Gather more light than the naked eye Magnify images. Telescopes. Best locations: Mountain peaks Because of thinner air and high elevations Desert climates Dry, clear skies Remote areas No city lights. Telescopes.

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Studying the Universe

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  1. Studying the Universe

  2. Telescopes • Telescopes aid astronomers in 2 ways • Gather more light than the naked eye • Magnify images

  3. Telescopes • Best locations: • Mountain peaks • Because of thinner air and high elevations • Desert climates • Dry, clear skies • Remote areas • No city lights

  4. Telescopes • Optical • Use lenses or mirrors to gather and focus starlight • Kept in domes to protect from the weather • Light gathering power depends on the area of the lens or mirror

  5. Refracting Telescope • Two lenses • Objective lens (end away from your eye) • Gathers starlight and bends it to form an image at the other end of the scope • Eyepiece lens • Magnifies the image for your eye

  6. Reflecting Telescopes • One large curved mirror gathers and focuses starlight • The large mirror is the objective • Has a secondary mirror to reflect the image to the observer • Also has an eyepiece lens to magnify the image

  7. Radio Astronomy • The study of radio waves given off by objects in space • Radio waves can pass through clouds of fine dust between stars (light rays can’t) • Can also be used during the day, when the stars can’t be seen

  8. Radio Telescopes • Look like satellite dishes used for TV • Made of solid metal or wire mesh • Collects and focuses radio waves • Radio waves have longer wavelengths, so radio telescopes must be bigger than opticals

  9. MMT • MMT = multiple mirror telescope • Several mirrors take the place of a single large mirror • Less expensive to build than single mirror

  10. Hubble Space Telescope • In orbit around Earth to avoid clouds and be closer to far away objects • Misshapen main mirror and other mechanical difficulties made it less effective • Computers have provided image correction technology so the telescope can be used

  11. Studying Energy • Stars emit light we can see….they also emit energy we cannot see • Electromagnetic energy – includes light, x-rays, radio waves, microwaves • Each type of energy has a different frequency and wavelength • All have the same velocity = 300,000 km per second

  12. Electromagnetic spectrum = the range of wavelengths from radio waves to gamma rays

  13. Describing Energy • Energy travels in waves… • Frequency = the number of waves that pass by a point in one second • Wavelength = distance from peak to peak or trough to trough • Frequency and wavelength are inversely proportional (as one goes up, the other goes down)

  14. Visible Spectrum • Visible spectrum = the range of wavelengths we can see • Each color of the rainbow has a different wavelength and frequency • All of the colors of the rainbow make up “visible” or “white” light • Red has a long wavelength, which means it bends less when passed through a prism

  15. Visible Spectrum • Spectroscope = a prism with a tiny viewing telescope • Separates light into its different colors • Spectrograph = prism with a lens and a camera, which records the spectrum

  16. Visible Spectrum • Seeing the colors of light allow astronomers to determine which chemical elements are present in the star’s outer layers • Spectra also allow astronomers to determine if the star is moving towards us or away from us

  17. Kinds of Visible Spectra • Continuous spectrum – unbroken band of colors, source is sending out all visible wavelengths of light • Can be produced from a glowing solid (light bulb) • Can be produced from a glowing liquid (molten iron) • Can be produced from the hot, compressed gases deep inside a star

  18. Kinds of Visible Spectra • Bright line spectrum – unevenly spaced series of lines of different colors and brightness • Source emits only certain wavelengths of light • aka – emission spectrum • Each element (as a gas) has a unique combination of colors

  19. Kinds of Visible Spectra • Dark line spectrum – continuous spectrum with dark lines where light is absorbed • Dark lines are in the same place as the bright lines • Form when light emitted by a star passes through a cooler gas • Gas absorbs the same wavelengths it would give off if heated • aka – absorption spectrum • Used to identify the element

  20. Emission spectra box • Tube is filled with a single element in the gaseous state • Electricity heats up the gas • The gas emits certain wavelengths of light • Combo of colors tells you what element you have

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