The tables are set in the State Dining Room of the White House for Friday's state dinner honoring visiting Chinese President Xi Jinping. Manuel Balce Ceneta/AP hide caption

itoggle caption Manuel Balce Ceneta/AP

President Barack Obama and Pope Francis stand at attention during the playing of the national anthems during a state arrival ceremony for the pope on the South Lawn of the White House Wednesday. Pablo Martinez Monsivais/AP hide caption

itoggle caption Pablo Martinez Monsivais/AP

U.S. Secretary of State John Kerry talks to U.S. Secretary of Energy Ernest Moniz during Iran nuclear deal negotiations. Carlos Barria/AP hide caption

itoggle caption Carlos Barria/AP

President Obama says Iran's "nuclear breakout" time will be extended from the current two or three months to at least a year under the nuclear agreement. But he acknowledges that some restrictions will fall away after 15 years and the breakout time would again shrink. Morgan Walker/NPR hide caption

itoggle caption Morgan Walker/NPR

President Obama spoke with Morning Edition host Steve Inskeep at the White House last week. Nick Michael/NPR hide caption

itoggle caption Nick Michael/NPR

A coal scraper machine works on a pile of coal at American Electric Power's Mountaineer coal power plant in 2009 in New Haven, W.Va. The state, in which coal mining is a major industry, is one party planning to sue the Environmental Protection Agency regarding new power plant regulations announced Monday. Saul Loeb/AFP/Getty Images hide caption

itoggle caption Saul Loeb/AFP/Getty Images

The Japanese supercomputer K, pictured in June 2012 at the RIKEN Advanced Institute for Computational Science in Kobe, western Japan. The K computer is currently ranked No. 3 on a list of the 500 fastest supercomputers. Kyodo/Landov hide caption

itoggle caption Kyodo/Landov