ns
nanosecond
Timeexact by definition
The nanosecond is 10⁻⁹ of a second, an exact SI prefix. Light travels almost exactly one foot in a nanosecond, which is the most useful rule of thumb in the unit: a signal down 10 feet of cable arrives about 10 ns late, and that delay is why cable length matters in fast digital design. Memory latency, logic propagation delay and radar ranging all live here.
| 1 ns | 1.0000000e-09 s |
Where the unit came from
Grace Hopper handed out 11.8-inch lengths of wire as "nanoseconds" to explain to admirals why satellite communication could not be instantaneous. The demonstration is still the clearest thing ever said about the unit.
Solvers that use time