Astronomy 123: Fourth Homework Assignment


  1. Explain how the "top-down" scenario for the formation of structure (e.g. galaxies, clusters of galaxies) in the Universe differs from the "bottom-up" scenario.

  2. Suppose you were arguing with someone about the Age of the Earth and your foe had an intrinsic distrust of science and its methods and so therefore would not believe anything to do with radioactive age dating.

    Outline what points of "common sense" about the nature of the Earth that you could use to demonstrate that the Earth must be at least millions of years old.

  3. Google on "quintessence" in relation to Dark Energy and summarize why some theorists believe that this is the nature of the Dark Energy.

  4. Our Galaxy appears to be long overdue for the occurrence of another Supernova. Find some information on Supernova rates for galaxies like ours and report those results. When was the last Supernova to occur in our galaxy? Based on the supernova rate, do you think that our Galaxy has been deficient in the production of supernova over the last few hundred years?

  5. Critically discuss the two leading theories for the origin of water on the Earth in terms of their overall credibility as the best explanation and cite any deficincies in these ideas.