1 nanosecond
1 nsTime · definition
Time conversions use a Julian year of exactly 365.25 days.
Time
Just how long is 1 nanosecond?
One nanosecond is one billionth of a second (10⁻⁹ s).
Fleeting instants
1 ns
ELAPSED TIME
1 nanosecond
Time conversions use a Julian year of exactly 365.25 days.
1 nsTime
0
Caesium-133 clock transition
The caesium-133 clock transition is the specific change in energy state of a caesium-133 atom that defines the duration of one second in the International System of Units.
108.8 psOne cycle
0
Both timelines start together. Length measures elapsed time, not a physical distance.
A little perspective
1 nanosecond is about 9.19 times one cycle of the caesium-133 clock transition.
Measurements, assumptions & sources +
1 nanosecond
Time: 1 ns; definition.
Time conversions use a Julian year of exactly 365.25 days.
Caesium-133 clock transition
One cycle: 108.8 ps; derived.
The SI second is defined from exactly 9,192,631,770 periods of the unperturbed caesium-133 ground-state hyperfine transition. The cycle duration and photon energy here are derived from that exact frequency.
BIPM — The International System of Units
The marked one cycle is calibrated. Unmeasured illustration details are representative.
Measurement details
Why these numbers?
Compare 1 nanosecond with one cycle of the caesium-133 clock transition. The notes below explain how each value was chosen.
Caesium-133 clock transition
108.8 psOne cycle · derived
The SI second is defined from exactly 9,192,631,770 periods of the unperturbed caesium-133 ground-state hyperfine transition. The cycle duration and photon energy here are derived from that exact frequency.
- Comparing
- Time ↔ One cycle
- Relative size
- 1 nanosecond is about 9.19 times one cycle of the caesium-133 clock transition. 1 nanosecond is approximately 819% greater than one cycle of the caesium-133 clock transition.
How to read the visual
The diagram uses the recorded measurements. Details outside the marked spans do not set the scale.
- One cycle of the caesium-133 clock transition: The measurement is labelled derived. Check the source notes for its basis.
A duration is an interval, not a calendar date.
1 × 10⁻⁹ sseconds
2.7778 × 10⁻¹³ hhours
1.1574 × 10⁻¹⁴ daysdays
3.1688 × 10⁻¹⁷ yearsyears
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