ASTR 122 Fourth Homework

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

  2. Do a google search or whatever on "Binary Neutron Stars" and report on why these systems are of interest to astronomers and what makes them special probes.

  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. At the other end of the scale are blackholes in the centers of galaxies that weigh 100 million solar masses. Derive the schwarschild radius for this kind of black hole and then compute its density and compare this with the density of the 1 earth mass black hole in the previous question. Does this comparison surprise you?

  5. 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?