ALEXANDER TSIARAS / SCIENCE PHOTO LIBRARY ALEXANDER TSIARAS / SCIENCE PHOTO LIBRARY
The CS2 caesium atomic clock at the German National Standards Laboratory, near Hannover. Caesium atomic clocks operate by counting the oscillations of vapourised caesium-133 atoms in an electromagnetic field. One second is equivalent to 9, 192,631,770 oscillations. The CS2 clock is the world's most accurate, losing about 3 billionths of a second a day (one second in one million years).
Model release not required. Property release not required.