We arrive at the library and hear a stimulating lecture on dueling cosmological theories and the influence of dark energy. I'm not sure I'm ready to take a test on the subject, but the talk was enjoyable and informative. We leave the library for a bracing walk back to our room (the wind is up and the temperature has dropped). Along the way Andrea helps me understand more about the Smithsonian's role in astronomy. Thus, a most interesting and worthwhile day comes to a close.