1. In class Monday, we talked about Jocelyn Bell's serendipitous discovery of what are now called "pulsars."  Suppose you discover, with your radio telescope (which is tuned to a particular reception frequency, as is a radio you might own), a source that varies in brightness with a very short period (say, 0.1 second).  Of paramount interest is that the period is consistently the same (to within one part in 10⁶ or 10⁷, a precision heretofore realized only by human-made atomic clocks).  Either you have discovered some new type of astronomical object or you have discovered the first communication from an alien intelligence.  There are  5 things that you might do or try to distinguish between the 2 possibilities; can you come up with at least 3 good ones?

  
2. Suppose the sun (rotation period = 25 days) collapsed to a neutron star size.  What would its rotation period be (in seconds)?   [You don't have to give me all the intermediate steps, but at least give me the physics principle and the basic method you used.]  Would this be short enough to account for the periods of known pulsars?

   3. A supernova explosion can only happen if a neutron star is formed.  Yet the vast majority of supernova remnants do not have a pulsar (a rotating neutron star) apparent inside of them. 

What might be the explanation for this absence? If you have done the reading on pulsars/neutron stars and supernovas, you should be able to come up with all 5 reasons.... but how about at least 3?