Astronomy 123 Third Homework Assignment




Due Wednesday Sept 2 by 10 pm




  1. 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.

  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. Given the available data on galaxy clustering, argue which scenario the data bests supports.

  3. 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.

  4. Research and then critically discuss

    • a) why there should be not that much water on the Earth and
    • b) given that the water exists, how did it most likely get to Earth?

  5. A dramatic new view of the geologic history of the Earth has arisen in the last few years. This view is quite controversial and is known as "Snowball Earth." Summarize what this theory is and what is some of the evidence for and against this hypothesis.

  6. The "RNA World" is an alternative hypothesis to the orgin of life. Do some research and determine how deep sea hydrothermal vents provides support to the RNA World Theory.