Lawrence Krauss, theoretical physicist, chair of the Bulletin of the Atomic Scientists Board of Sponsors, left, and Thomas Pickering, co-chair of the International Crisis Group, display the Doomsday Clock during a news conference the at the National Press Club in Washington, Thursday, Jan. 26, 2017, announcing that the Bulletin of the Atomic Scientist have moved the minute hand of the Doomsday Clock to two and a half minutes to midnight. (AP Photo/Carolyn Kaster)