Module 24: Galaxies and the Universe

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Across
  1. 1. A possible outcome of the universe where the expansion slows to a halt in an infinite amount of time but never contracts. (page 680)
  2. 6. Persistent background noise that appears to come from all directions. (three words – page 680)
  3. 9. The study of the universe – its nature, origin, and evolution is called _____. (page 679)
  4. 11. Determining Hubble’s Constant (H) is a difficult task because it is hard to measure accurate distances to the most remote _____. (page 675)
  5. 12. Measured the redshift and distances of many galaxies and found that the farther away a galaxy is, the faster it is moving away. (page 674)
  6. 16. Type of galaxy that are extremely luminous and are often giant elliptical galaxies that emit as much energy in radio wavelengths as they do in wavelengths of visible light. (page 676)
  7. 17. The age of the universe is 13.7 _____ years. (page 679)
  8. 18. By making a graph comparing a galaxy’s _____ to the _____ at which it is moving, Hubble determined that the universe is expanding. (page 675)
  9. 19. The label astronomers have given to the reason of the acceleration of the universe. (two words – page 681)
Down
  1. 2. When the rate of expansion of the universe is known, it is possible to calculate the _____ since the expansion started and determine the _____ of the universe. (two words – page 679).
  2. 3. A possible outcome of the universe where the expansion will never stop. (page 680)
  3. 4. A possible outcome of the universe where the expansion stops and becomes a contraction. (page 680)
  4. 5. Starlike objects with emission lines in their spectra. (page 676)
  5. 7. According to every standard model, the expansion of the universe is _____ _____ due to gravity. (two words - page 681)
  6. 8. A surprising discovery showed that the expansion of the universe is now _____. (page 681)
  7. 10. The short-wavelength radiation that filled the universe 300,000 years after it formed expanded into radiation in the form of _____. (page 680)
  8. 13. If the universe is expanding now, it must have been _____ and _____ in the past. (two words – page 675)
  9. 14. The theory that the universe began as a point and has been expanding ever since is called _____ (two words – page 679)
  10. 15. Galaxies that emit large amounts of energy from their cores are called _____ galaxies. (page 675)