nanotesla

Nanotesla (nT) is the SI derived unit of magnetic flux density, equal to one billionth of a tesla. It is used to express relatively weak magnetic fields that are common in geophysics, space science, and laboratory magnetism. The tesla is the base unit for magnetic flux density, so 1 nT equals 1 × 10^-9 T.

In practical terms, nanotesla helps quantify natural and experimental magnetic fields that are much smaller than the strong fields produced by MRI devices or industrial magnets. For reference, 1 microtesla (µT) is 1,000 nT, and 1 gauss is 100,000 nT. The Earth's magnetic field at the surface typically ranges from about 25,000 to 65,000 nT, depending on location. Variations due to solar activity or local geology are often reported in nanotesla.

Nanotesla is also the common reporting unit for high-sensitivity magnetometers, including fluxgate sensors and SQUID-based instruments, which are designed to detect small changes in magnetic flux density. The unit is widely used in geophysics, archaeology, space weather studies, and laboratory experiments where precise measurements of weak magnetic fields are required.

The term nanotesla reflects the SI convention of combining the nano- prefix with the tesla. Its usage remains straightforward: 1 nT equals 10^-9 tesla, and larger or smaller magnetic fields are expressed by applying the appropriate SI prefix.