Astronomy 123 Third Homework Assignment




Due Wed Feb 26 by 10 pm

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  1. Recent evidence suggests that the Universe is filled with something termed "Dark Energy". What is evidence for the existence of dark energy and what are some hypothesis as to what it is? Note that this question is asking about Dark Energy NOT Dark Matter (covered already in class)

  2. 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. (Google on terms like: top-down galaxy formation and/or bottom-up galaxy formation)

  3. Do some research on the concept of "Modified Newtonian Dynamics" or MOND. Discuss the basic idea of MOND and state whether or not you think its a credible alternative to the need for Dark Matter, which we still have not yet detected.

  4. 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.

  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 weaknesses in these ideas.