Attohertz (aHz): SI Unit for Ultra-Low Frequencies
The attohertz (symbol: aHz) is an SI-derived unit of frequency equal to 10−18 hertz. It combines the SI prefix atto-, meaning one quintillionth, with the hertz, the SI derived unit of frequency. The attohertz provides a standardized way to represent extremely low frequencies using the International System of Units (SI).
What Is an Attohertz?
An attohertz is a unit of frequency equal to 10−18 hertz. A frequency of one attohertz corresponds to one cycle occurring over an extraordinarily long period, making the unit suitable for describing extremely slow periodic events.
The attohertz is one-thousandth of a femtohertz and one thousand zeptohertz. It helps simplify scientific notation when representing exceptionally small frequency values.
History of the Attohertz
The atto- prefix was officially adopted by the International Bureau of Weights and Measures (BIPM) in 1964 as part of the International System of Units (SI). When combined with the hertz, it forms the attohertz, allowing standardized representation of frequencies as small as 10−18 hertz.
Current Uses of the Attohertz
Attohertz is primarily used in theoretical physics, cosmology, astronomy, geophysics, and advanced scientific research involving extremely slow oscillations or long-period phenomena. Although it is rarely encountered in practical engineering, it provides a consistent SI unit for expressing ultra-low frequencies.
Attohertz Conversion
One attohertz is equal to:
- 1 × 10−18 hertz (Hz)
- 0.001 femtohertz (fHz)
- 1,000 zeptohertz (zHz)
- 0.000001 picohertz (pHz)
You can use ChangeUnit to convert attohertz to hertz, femtohertz, zeptohertz, and many other frequency units.