Astronomy Club Meeting and Carmen Austin's Presentation!

Astronomy Problems of the Week (Meeting Thursday at 3:30pm, Steward 450):

Puzzle #1:
Four identical sealed envelopes are on a table. One contains a $100 bill. You select an envelope at random and hold it in your hand without opening it. Two of the remaining three envelopes are then removed and set aside, still sealed. You are told that they are empty. You are now given the choice of keeping the envelope you selected or exchanging it for the one on the table. What should you do:

A). Keep your envelope.
B). Switch it;
C). It doesn’t matter.

Puzzle #2:
How many different astronomical phenomena can you find in the attached image?
Are these phenomena shown to scale?
How could you improve the diagram?