Your clocks are about to shift! At the end of June, a leap second will be added to the global time reference. This change will be tracked by the working atomic clock on display in the Time and Navigation exhibition. In this presentation, learn why leap seconds have been added and how time is synchronized around the world. 

Meet at the Museum "Great Seal", in the Boeing Milestones of Flight Hall on the first floor.

About the Ask an Expert lecture series: Every Wednesday at noon in the National Mall Building, a Museum staff member talks to the public about the history, collection, or personalities related to a specific artifact or exhibition in the Museum.

 Visitors at the National Mall building enjoy learning about the Pioneer 10 spacecraft from Museum scientist Andrew Johnston. Short Ask an Expert lectures such as this are offered once a week. Pioneer 10 was the first spacecraft to fly by Jupiter, the largest planet in the Solar System. How to attend

National Air and Space Museum in Washington, DC

6th St. and Independence Ave SW. Washington, DC 20560