Astronomy Chapter one

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Astronomy Chapter one
2012-04-03 19:26:21
Astronomy Chapter One

key terms and concepts
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  1. Field of view
    the region you can see in am image
  2. Scientific notation
    the system of recording very large or very small numbers by using the power of ten
  3. planet
    a small nonluminous body that shines by reflected light
  4. star
    a globe of gas held together by its own gravity and supported by the internal pressure of its hot gasses, which generate energy by nuclear fusion
  5. astronomical unit
    the average distance from Earth to the sun:


    1.5 x 108 km, or 93 x 106 mi
  6. light year (ly)
    a unit of distance; the distance light travels in one year

    1013 km or 63,000 AU
  7. galaxy
    a large system of stars, star clusters, gas, dust, and nebulae orbiting a common center of mass
  8. Milky Way Galaxy
    the spiral galaxy containing our sun; it is visible in the night sky as the Milk Way
  9. Spiral arm
    a long spiral pattern of bright stars, star clusters, gas, and dust. Such arms extend from the center to the edge of the disk of spiral galaxies