Got a second? Time & Navigation exhibit at the Smithsonian

The National Air & Space Museum and the National Museum of American History have joined forces to create a new permanent exhibition at the Air & Space Museum in Washington, D.C. called Time and Navigation: The Untold Story of Getting from Here to There.

Winnie Mae

Wiley Post’s Winnie Mae circled the globe two times, shattering previous records.
Photo: Eric Long, Smithsonian

The new exhibit explores how revolutions in timekeeping allowed people to find their way and includes sections about navigation at sea, in the air and in space,

Great on-line resources include a Timeline of Innovation, which notes that a new and more accurate definition of a second – the basic unit of time – was adopted in 1967.

“The new second was based on the duration of 9,192,631,770 periods of radiation in an isotope of cesium. Previously, the second had been defined as 1/86,400th of the mean solar day. The change was momentous. Atomic clocks had demonstrated that the unvarying vibrations of atoms were more accurate timekeepers than the irregular daily rotation of the Earth.”

Definition of a second

A new second. courtesy National Air & Space Museum