Chapter 9 Flash Cards

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Chapter 9 Flash Cards
2013-01-15 20:00:49
Earth Space Science

Chapter 9 Key Terms
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  1. Milky Way
    • The galaxy that includes the solar system
    • Appears as a hazy white band in the night sky
  2. Galaxy
    • A huge collection of stars, planets, gas, and dust that is held together by gravity
  3. Star cluster
    • A collection of stars held together by gravity
    • The picture below shows the two types of cluster
  4. Open cluster
    • A collection of 50 to 1 000 stars
    • Open clusters appear along the main band of the Milky Way
  5. Globular cluster
    • A collection of 100 000 to 1 000 000 stars, which are arranged in a distinctive spherical shape
    • They appear around the center of the Milky Way
  6. Local group
    • The small group of galaxies that includes the Milky Way
  7. Supercluster
    A gigantic cluster of 4 to 25 cluster of galaxies, which is hundreds of millions of light-years in size
  8. Shapes of galaxies
    • There are 3 shapes of galaxies.
    • 1. Spiral Galaxy- looks like a pinwhell from above
    • 2. Elliptical Galaxy- looks like a stretched out sphere into an ellipse
    • 3. Irregular Galaxy- do not have a regular shape.
  9. Cosmology
    The study of the universe
  10. Doppler effect
    • The change in frequency of a light source due to its motion relative to the observer
    • The change in pitch is due to the motion of the source relative to an observer
  11. Redshift
    • The effect in which objects moving away from an observer have their wavelengths lenghtened, toward the red end of the visible spectrum
    • The third spectra above is redshifted
  12. Blueshift
    • The effect in which objects moving toward an observer have their wavelengths shortened, toward the blue end of the visible spectrum
    • The second spectra above is blueshifted
  13. Big bang
    The event that may have triggered the expansion of thte universe 14 billion years ago
  14. Cosmic microwave background (CMB) radiation
    • The radiation left over from the big bang, which fills the universe
  15. Dark matter
    • The most abundant form of matter in the universe
    • It is invisible to telescopes
  16. Dark energy
    • A form of energy that makes up nearly three quarters of the universe, which has the effect of increasing the expanding of the universe