Astronomy 122: Fourth Homework Assignment


  1. Summarize the methods that astronomers use to detect the presence of Black Holes, even though they themselves emit no light.

  2. 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?

  3. The Schwarschild radius (e.g. the radius of the event horizon) of a 1 solar mass black hole is 3 kilometers. Calculate (show your work) the schwarschild radius of a 1 earth mass black hole.

  4. Explain how a 1 solar-mass pre-main sequence star is able to radiate more energy than when that star becomes a main-sequence star and derives energy from nuclear fusion in the core.

  5. Despite the fact that we think we know everything, the origin of the relatively large amount of water (compared to other planets) that is on the Earth remains mysterious. Do some research and summarize what you feel are the most credible explanations for how the Earth got most of its water (note: the explanation in the lecture pages may or may not be credible).