Chapter 9 Science

  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
  4. Open Cluster
    A collection of 50 to 1000 stars: open clusters appear along the main band of the Milky Way
  5. Globular Cluster
    A collection of 100 000 to a million stars that is arranged in a distinctive spherical shape; globular clusters are around the centre of the Milky Way
  6. Local Group
    The small group of about 40 galaxies that includes the Milky Way
  7. Supercluster
    A gigantic cluster of 4 to 25 clusters of galaxies that is hundreds of millions of light-years in size
  8. Shapes of Galaxies
    Thanks to the work of Edwin Hubble we know that just about any galaxy in the universe will have one of 4 different shapes, spiral, elliptical, lenticular, and irregular.
  9. Cosmology
    the study of the universe
  10. Doppler Effect
    The change in pitch of a sound due to the motion of the source relative to an observer; also, the change in frequency of a light source due to its motion relative to an observer
  11. Redshift
    The effect in which objects moving away from an observer have their wavelengths lengthened toward the red end of the visible spectrum
  12. Blueshift
    The effect in which objects moving towards an observer have their wavelengths shortened, toward the blue end of the visible spectrum
  13. Big Bang
    The event that may have triggered the expansion of the 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; invisible to telescopes
  16. Dark Energy
    A form of energy that makes up nearly three quarters of the universe; has the effect of increasing the expansion of the universe
Card Set
Chapter 9 Science