Zeptohertz (zHz): SI Unit for Extremely Low Frequencies
The zeptohertz (symbol: zHz) is an SI-derived unit of frequency equal to 10−21 hertz. It combines the SI prefix zepto-, meaning one sextillionth, with the hertz, the SI derived unit of frequency. The zeptohertz enables scientists to express extremely small frequency values using standardized SI notation.
What Is a Zeptohertz?
A zeptohertz is a unit of frequency equal to 10−21 hertz. A frequency of one zeptohertz corresponds to one complete cycle over an extraordinarily long time, making the unit suitable for describing extremely slow periodic phenomena.
The zeptohertz is one-thousandth of an attohertz and one thousand yoctohertz. It simplifies the representation of extremely small frequencies that would otherwise require cumbersome scientific notation.
History of the Zeptohertz
The zepto- prefix was officially adopted by the International Bureau of Weights and Measures (BIPM) in 1991 as part of the International System of Units (SI). When combined with the hertz, it forms the zeptohertz, providing a standardized SI unit for frequencies as small as 10−21 hertz.
Current Uses of the Zeptohertz
Zeptohertz is primarily used in theoretical physics, cosmology, astronomy, geophysics, and advanced scientific modeling involving extremely slow oscillations or long-period events. While rarely encountered in practical engineering, it offers a consistent SI unit for expressing ultra-low frequencies.
Zeptohertz Conversion
One zeptohertz is equal to:
- 1 × 10−21 hertz (Hz)
- 0.001 attohertz (aHz)
- 1,000 yoctohertz (yHz)
- 0.000001 femtohertz (fHz)
You can use ChangeUnit to convert zeptohertz to hertz, attohertz, yoctohertz, and many other frequency units.