David Helfand has been a Professor of Astronomy at Columbia University for 47 years, where he served as chair of the Department for two decades. He is also the former President of the American Astronomical Society and of Quest University Canada, and currently serves as Chair of the American Institute of Physics. Professor Helfand has received the Columbia Presidential Teaching Award and the Great Teacher Award from the Society of Columbia Graduates. He is the author of A Survival Guide to the Misinformation Age and, recently The Universal Timekeepers: Reconstructing History Atom by Atom.