In honor of our first anniversary we invited Historian Timothy Alborn to help us understand the arbitrary nature of anniversaries, both those that mark events of personal significance and those that have a wider societal impact. We chose to record this episode on a very special "holiday": Perihelinox. If you've never heard of it it's because it was recently made up by our producer, Benny Pollak, to celebrate the night of the year when the earth is closest to the sun. Nothing is sacred in this episode, from Christmas to Kwanza, to Hanukkah, to Royal Jubilees. And, the Sex Pistols?

Timothy Alborn is a historian and the Dean of Arts and Humanities at the City University of New York—Lehman College (and, incidentally, Massimo's boss). He has a Ph.D. in History of Science from Harvard University. His recent publications include "Regulated Lives: Life Assurance and British Society, 1840-1920" and "Conceiving Companies: Joint-Stock Politics in Victorian England."