A Second is a unit of time.
Modern Imperial usage defines the second as "the duration of 9,192,631,770 periods of the radiation corresponding between the two hyperfine levels of the ground state of the caesium-133 atom".
- The ability to accurately interpret this value is gained at around TL-6, with the advent of sophisticated electronic computers.
- The common Imperial abbreviation is sec.
A second is considered to be the smallest unit of time within which a meaningful interaction or reaction can take place. While this may be true for a typical human, other species or sophont races may have alternative perceptions of – and ability to act within – the passage of a single second.
MKS and CGS Units
The MKS system of units is a physical system of measurement based on the meter as the unit of length, the kilogram as the unit of mass, and the second as the unit of time. Smaller scale measurements may utilize the CGS system, based on the centimeter as the unit of length, the gram as the unit of mass, and the second as the unit of time. The system has broad applications within science, engineering and commerce.
Other interstellar cultures have different values for the second.
The second was defined as a unit of time on Terra prior to the foundation of the Terran Confederation. It was originally calculated as being 1/86,400th of a complete rotation of the planet (a Terran day).