death and birth of stars

1. Most black holes, even though they emit no light themselves, have been detected in various X-ray surveys. Explain the process that leads to X-ray emission in the near vicinity of the Black Hole. 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 Schwarzschild radius (e.g. the radius of the event horizon) of a 1 solar mass black hole is 3 kilometers. Calculate (show your work) the Schwarzschild radius of a 1 earth mass black hole. (you can do this problem without plugging into any formula if you think about it) 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. This questions will count the most on this particular homework assignment so put some research effort into it: Critically discuss the two leading theories (you will have to decide for yourself what those two leading theories are) for the origin of water on the Earth in terms of their overall credibility as the best explanation and discuss possible problems with each theory as being the best explanation.